Dual SIM with eSIM: Two Numbers on One Phone (Calls, OTPs, Data)

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Dual SIM with eSIM: Two Numbers on One...

Dual SIM with eSIM: Two Numbers on One Phone (Calls, OTPs, Data)

30 Oct 2025

eSIM
Dual SIM with eSIM: Two Numbers on One Phone (Calls, OTPs, Data)

Staying reachable without burning money on roaming is the modern traveller’s headache. Dual SIM with eSIM solves it: keep your main number active for calls and OTPs, and add a low-cost local or regional data plan on the same phone. No SIM swapping. No missed texts from your bank. In this guide, we explain how dual SIM with eSIM works, how calls/SMS/data behave, and how to set it up on iPhone and Android. We also cover common use cases like work/personal separation and travel/local pairing, plus how WhatsApp and other apps handle two numbers. If you’re planning a trip, browse country and regional options via Destinations or pick ready-made bundles such as Esim Western Europe or Esim North America. For the US or single-country trips, see Esim United States, Esim France, Esim Italy and Esim Spain.

What is dual SIM with eSIM?

Dual SIM means your phone can maintain two mobile lines at once. One or both can be eSIMs (digital SIM profiles). Typical setups: - Physical SIM + eSIM active together. - Two eSIMs active (on many newer devices). - Multiple eSIM profiles stored, with up to two active at a time (device-dependent).

On dual SIM dual standby (DSDS) phones, both lines are “on” for calls and texts when idle. You set a default line for data, calls and messages, and you can switch defaults at any time.

Device support varies. Recent iPhones and most mid/high-end Android phones support dual SIM with eSIM, but some models allow only one eSIM active at a time or restrict 5G/VoLTE on the secondary line. Check your device’s specs before you travel.

Why use dual SIM eSIM? Practical use cases

Work and personal separation

  • Keep your personal number private while making and receiving work calls on a second line.
  • Set the default for outgoing calls to your work line during office hours and flip it back to personal later.
  • Mute one line at set times to reduce interruptions without missing urgent personal calls.

Travel: keep your home number for OTPs, add local data

Coverage and cost optimisation

  • Use the line with stronger coverage for data in fringe areas.
  • Keep a cheap voice/SMS plan on one line and a high-data plan on the other.
  • Switch defaults on the fly when you cross borders or move between networks.

Teams, events and short-term projects

  • Provision temporary eSIM lines for contractors, events or field staff without shipping plastic SIMs.
  • Centrally manage usage and budgets; see For Business.
  • Partners and resellers can streamline deployments via the Partner Hub.

How calls, SMS, data, OTPs and apps behave

Understanding how two lines interact avoids surprises.

  • Calls in standby: Both lines can receive calls when idle. When you place or receive a call on one line, the other may go to voicemail or show as unreachable unless your device/network supports features like call waiting across lines or Wi‑Fi Calling. Behaviour varies by carrier and phone.
  • Default for voice/SMS: You choose a default line for outgoing calls and texts, but you can select the other line per contact or per call.
  • Mobile data: Only one line provides mobile data at a time. You set this in settings. Some phones support “allow mobile data switching”, automatically using the other line if the selected data line has weak signal.
  • SMS-based OTPs: OTP texts arrive on the line tied to that number as long as that line is enabled and has signal. Data does not need to be enabled on that line. If you’re abroad, receiving OTPs may incur roaming SMS charges on your home line—turn off data roaming but keep SMS/calls enabled to control costs.
  • iMessage/FaceTime (iPhone): You can enable iMessage/FaceTime for one or both numbers and choose which to use by default.
  • WhatsApp and similar apps:
  • The standard WhatsApp app supports one number per device. Data can come from either line.
  • To run two WhatsApp accounts on one phone, use WhatsApp + WhatsApp Business (iOS/Android) or OEM dual-app features (on some Android devices).
  • Your WhatsApp number does not change just because your data comes from your travel eSIM.

Set-up: dual SIM with eSIM

iPhone step-by-step

  1. Obtain your eSIM details: QR code or activation code from your provider.
  2. On iPhone, go to Settings > Mobile Data > Add eSIM (or “Add Data Plan”).
  3. Scan the QR code or enter details. Wait for activation.
  4. Label your lines (e.g., “Personal” and “Travel”). Clear labels prevent mistakes.
  5. Choose defaults: - Default Line for Calls and SMS. - iMessage & FaceTime line. - Mobile Data line (set to your travel/local eSIM when abroad).
  6. Toggle “Data Roaming”: - Turn off for your home line while travelling. - Turn on for your travel eSIM, if required.
  7. Optional: Enable “Allow Mobile Data Switching” if you want automatic fallback.
  8. Test: Place a call from each line, send yourself an SMS from another phone, and load a webpage to confirm the data line.

Pro tips for iPhone: - You can store multiple eSIMs and swap which are active. Many newer iPhones support two active eSIMs. - Backups don’t include eSIMs. Keep your activation details safe; some carriers limit re-downloads. - For Wi‑Fi Calling, enable it separately per line (Settings > Phone > Wi‑Fi Calling).

Android step-by-step (Pixel/Samsung and similar)

  1. Get your eSIM QR/activation details from your provider.
  2. Open Settings > Network & Internet (or Connections) > SIMs > Add eSIM.
  3. Scan the QR code or enter details. Wait for activation.
  4. Name each SIM (e.g., “Work” and “Data”).
  5. Set preferences: - Preferred SIM for Calls. - Preferred SIM for SMS. - Preferred SIM for Mobile Data (set to the travel/local eSIM).
  6. Roaming: - Disable data roaming on your home line. - Enable on your travel eSIM if needed.
  7. Optional: Enable “Switch data automatically” or similar to allow fallback.
  8. Test calls, SMS, and data on both lines.

Pro tips for Android: - Some phones let you duplicate apps (Dual Messenger/App Twin) to run two WhatsApp accounts. Alternatively, use WhatsApp + WhatsApp Business. - Not all Android models support two eSIMs active simultaneously. If yours doesn’t, use one physical SIM + one eSIM, or swap active eSIM profiles as needed. - VoLTE/5G availability can differ per SIM slot/line; check your device and carriers.

Travel checklist: avoid bill shock and stay reachable

Before you fly: - Install and activate your travel eSIM over Wi‑Fi at home. - Label lines clearly and set the travel eSIM as the Mobile Data line. - Turn off Data Roaming on your home line; leave Calls and SMS on if you need OTPs. - Enable Wi‑Fi Calling for your home line if supported, to improve reachability without roaming data. - Check voicemail and call forwarding settings for both lines. - Tell your bank you’re travelling; ensure OTPs can arrive via SMS or app. - Save carrier support contacts and your eSIM activation details offline.

On arrival: - Confirm the travel eSIM connects and data works. - Place a brief test call from each line and send a test SMS. - Keep an eye on status bar icons to ensure you’re not accidentally using data on the home line.

Pro tips and common gotchas

  • Keep eSIM credentials safe: Many providers allow limited re-installs. Don’t delete an active eSIM while abroad unless you’re certain you can re-download it.
  • One data line at a time: Even with two active lines, only one provides mobile data. Choose carefully for maps, ride-hailing and tethering.
  • Call collisions: During a call on one line, the other may be unreachable on some networks. If that’s critical, enable Wi‑Fi Calling and test how your phone behaves.
  • Battery impact: Two active lines can use more battery. Mitigate by disabling 5G on the non-data line, reducing background activity, and using Wi‑Fi where possible.
  • Apps tied to a number: Services like WhatsApp, Signal and Telegram can be re-registered to another number, but you may lose message history or access. Decide which number you want long-term before switching.
  • Region-savvy plans: Multi-country eSIMs like Esim Western Europe simplify border crossings; US/Canada/Mexico travellers can look at Esim North America. Compare options by country on Destinations.

Regional picks for travellers

FAQs

  • Can I use both numbers at the same time?
  • Yes, both lines are on standby for calls and texts. Only one line provides mobile data at a time. If you’re on a call on one line, the other may be temporarily unreachable depending on device/network features.
  • Will OTP texts arrive while my data is on the other eSIM?
  • Yes. OTPs arrive on the line associated with that number as long as that line is enabled and has signal. Data does not need to be on for SMS. Roaming SMS fees may apply if you’re abroad on your home line.
  • Can I use WhatsApp with two numbers on one phone?
  • The standard app supports one number. To run two accounts, use WhatsApp + WhatsApp Business (works on iOS and Android) or an OEM dual-app feature on some Android phones. Your data can come from either line regardless of the WhatsApp number.
  • How do I avoid roaming charges on my home SIM?
  • Turn off Data Roaming for the home line. Keep Calls and SMS on if you need to receive OTPs or critical calls. Set your travel eSIM as the Mobile Data line. Consider Wi‑Fi Calling to improve reachability without data roaming.
  • Does dual SIM affect battery life?
  • Slightly, because the phone maintains two network registrations. Reduce impact by disabling 5G on the non-data line, using Wi‑Fi, and turning off the secondary line when not needed.
  • What if my phone supports only one eSIM active at a time?
  • Use one physical SIM plus one eSIM, or store multiple eSIM profiles and switch which is active as required. Check your device manual for limits on active lines and 5G support.

Next step: Plan your trip and pick the right travel eSIM by browsing Destinations.

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Andes Highlights (3 Weeks): Peru–Bolivia–Chile–Argentina Connectivity

Andes Highlights (3 Weeks): Peru–Bolivia–Chile–Argentina Connectivity

Planning a south america itinerary 3 weeks through the high Andes? This route stitches together Peru’s Sacred Valley, Bolivia’s La Paz and Salar de Uyuni, Chile’s Atacama Desert, and northern Argentina’s quebradas or Mendoza wine country—often by long-distance bus and a couple of short flights. Connectivity is different at altitude: coverage is strong in cities but drops in high passes and salt flats; bus Wi‑Fi is patchy; border towns can be blackspots. The smart move is an eSIM with multi‑country coverage, backed by offline maps, offline translations, and a simple routine for crossing borders by bus without losing service. Below you’ll find a practical, connectivity-first itinerary; checklists to prep your phone, apps and documents; and on-the-ground tips for staying online where it matters: booking transport, hailing taxis, backing up photos, and navigating when the signal disappears.If you’re transiting via Europe or North America, you can also add a layover eSIM to stay connected door-to-door. Start with our country list on Destinations, then follow the steps, and you won’t waste time chasing SIM shops at 3,500 metres.The 3‑week Andes route at a glanceWeek 1: Peru (Cusco, Sacred Valley, Machu Picchu) - Fly into Cusco (or Lima then connect). - Base in Cusco; day trips to Pisac/Chinchero/Maras–Moray. - Train to Aguas Calientes; Machu Picchu visit; return to Cusco or continue to Puno/Lake Titicaca.Week 2: Bolivia and Chile (La Paz, Uyuni, San Pedro de Atacama) - Bus/collectivo via Copacabana to La Paz. - Fly or overnight bus to Uyuni. - 3‑day Uyuni–altiplano tour ending in San Pedro de Atacama (Chile).Week 3: Chile and Argentina (Atacama to Salta or Mendoza/Buenos Aires) - Choose: - North: San Pedro to Salta/Jujuy by bus; fly to Buenos Aires. - Or South: San Pedro–Calama flight to Santiago; bus or flight to Mendoza; onward to Buenos Aires.Connectivity notes (quick): - Cities: generally strong 4G/4G+; 5G in major hubs (Santiago, Buenos Aires). - Altitude/rural: expect long no‑signal stretches (Uyuni, altiplano passes, Paso Jama). - Bus Wi‑Fi: often advertised, rarely reliable. Plan to be offline onboard. - Border regions: networks switch; a multi‑country eSIM avoids sudden loss.eSIM vs local SIMs for a 4‑country tripFor a route with multiple borders and remote legs, eSIM wins on time and reliability.What a multi‑country eSIM gets you: - One plan across Peru, Bolivia, Chile, Argentina (check coverage per country on Destinations). - No passport/SIM registration queues at kiosks. - Keep your home number active on the physical SIM for calls/SMS codes. - Instant top‑ups if you burn data on photos or navigation.When a local SIM still helps: - Long stay in one country with heavy data use (e.g., a month in Buenos Aires). - Dead zones where a different local network performs better (rarely worth the hassle on a 3‑week pace).Practical approach: - Use an eSIM as your primary data line across all four countries. - If you find a specific local network far better in one region, add a cheap local SIM and keep the eSIM as backup.Device readiness checklist (before you fly)1) Check eSIM compatibility and SIM‑lock status on your phone.2) Buy and install your eSIM while on home Wi‑Fi. Keep a PDF/printed copy of the QR code.3) Label lines clearly (e.g., “eSIM Andes Data”, “Home SIM”).4) Turn on data roaming for the eSIM; leave roaming off for your home SIM to avoid charges.5) Set up dual‑SIM rules: data on eSIM; calls/SMS default to home SIM if needed.6) Download offline: Google Maps/Organic Maps for all target regions; language packs (Spanish at minimum); bus/air tickets; hotel confirmations.7) Cloud backups: set to upload on Wi‑Fi only; pre‑create shared albums for travel companions.8) Test tethering/hotspot with your laptop/tablet.If you’re transiting popular hubs, consider a short layover eSIM: - USA connections: add an Esim United States or a broader Esim North America.- Europe connections: Madrid/Barcelona? Use an Esim Spain. Paris or Rome? See Esim France and Esim Italy. Multi‑country layovers? Try Esim Western Europe.City‑by‑city connectivity notesCusco & the Sacred Valley (Peru)Coverage: Good in Cusco city; variable in high villages (Maras/Moray) and along Inca Trail approaches.Tips: Download Sacred Valley maps offline; pin viewpoints and ruins. most taxis use WhatsApp—save your accommodation’s number.Machu Picchu/Aguas Calientes: Patchy to none at the citadel. Upload your photos later; don’t rely on live ticket retrieval.Lake Titicaca: Puno and CopacabanaPuno: Reasonable 4G; bus terminals crowded—screenshot QR tickets.Crossing to Copacabana: Expect a signal drop around the border; have directions saved offline.La Paz (Bolivia)Good urban 4G; the cable car network has decent signal but tunnels do not.Yungas/“Death Road” tours: Mountain valleys cause dead zones—share your emergency contacts with the operator, carry a charged power bank, and don’t plan remote calls.Uyuni and the Altiplano (Bolivia to Chile)Uyuni town: OK 4G; ATMs finicky—use Wi‑Fi for banking apps.Salt flats/lagunas: Assume offline for most of the 3‑day tour. Guides often carry satellite phones; agree a pickup time/place in San Pedro and preload your map route.San Pedro de Atacama (Chile)Town: Solid 4G; accommodations often have Wi‑Fi but speeds vary.Geysers, Valle de la Luna: Offline navigation essential; sunrise trips start before mobile networks wake up in some areas.Salta/Jujuy or Mendoza/Buenos Aires (Argentina)Salta/Jujuy: Good city coverage; quebradas have long no‑signal sections.Mendoza: City 4G/5G; vineyards outside town can be patchy.Buenos Aires: Strong 4G/5G; ideal for cloud backups and large downloads before you fly home.Border crossings by bus: step‑by‑stepThe big ones on this route: Peru–Bolivia (Puno/Copacabana), Bolivia–Chile (Uyuni–San Pedro via Hito Cajón), Chile–Argentina (Paso Jama to Salta or Los Libertadores to Mendoza).How to keep service and sanity:1) The day before:- Top up your eSIM data.- Confirm your plan includes both countries you’re entering/leaving.- Download offline maps for both sides of the border and your town of arrival.- Save bus company WhatsApp and terminal address offline.2) On departure morning:- Keep a paper copy or offline PDF of tickets, insurance, and accommodation proof.- Charge phone and power bank; pack a short cable in your daypack.3) On the bus:- Don’t count on bus Wi‑Fi. Keep your eSIM as primary, but expect drops near mountain passes.- If your phone supports it, enable “Wi‑Fi calling” for later when you reach accommodation Wi‑Fi.4) At the border posts:- Data may be unavailable. Keep QR codes and booking numbers offline.- After exiting one country and entering the next, toggle Airplane Mode off/on to re‑register on the new network.- If the eSIM doesn’t attach, manually select a network in Mobile Settings.5) Arrival:- Send your accommodation a quick WhatsApp when you’re back online.- Recheck your eSIM’s data roaming is on; confirm you’re on an in‑country network, not a weak roaming partner.Pro tips: - Dual profiles: If your eSIM allows, keep a secondary profile for a different network in the same country—helpful in border towns.- Cash buffer: Some border terminals don’t accept cards; download a currency converter for offline use.Offline survival kit (5‑minute setup)Maps: Download regions for Cusco, Sacred Valley, Puno, La Paz, Uyuni, San Pedro, Salta/Jujuy or Mendoza, and Buenos Aires.Translations: Download Spanish for offline use; add phrasebook favourites (bus tickets, directions, dietary needs).Documents: Save PDFs of passports, tickets, hotel addresses; star them for quick access.Rides: Screenshots of pickup points; pin bus terminals and hotel doors.Entertainment: Podcasts and playlists for long bus legs, set to download on Wi‑Fi only.Altitude and your tech: what changesCoverage gaps lengthen: Fewer towers at high altitude; valleys can block signal. Assume offline on remote excursions.Batteries drain faster in cold: Keep your phone warm and carry a power bank (10,000–20,000 mAh).Hotel Wi‑Fi may be congested: Schedule big uploads (photo backups, app updates) for big-city stays like Santiago or Buenos Aires.GPS still works offline: Your blue dot shows on offline maps without data—preload everything.Data budgeting for 3 weeksTypical traveller usage across this route: - Messaging/Maps/Bookings: 0.2–0.5 GB/day- Social and photo sharing: 0.3–0.7 GB/day- Occasional video calls/streaming: 0.5–1.0 GB/dayFor a mixed-use trip, plan 15–25 GB for 3 weeks. Heavy creators should double it and upload over hotel Wi‑Fi when possible. If you work remotely, consider a higher‑capacity plan and a backup eSIM; see our guidance on For Business.Practical route with transport and connectivity cuesDays 1–4 Cusco base: Strong city signal; day trips may be spotty—go offline-ready.Days 5–6 Machu Picchu: Expect no service at the ruins; sync tickets ahead.Days 7–8 Puno to La Paz via Copacabana: Border signal drop; re‑register networks after crossing.Days 9–11 Uyuni tour to San Pedro: Treat as offline; charge nightly; carry spare cables.Days 12–14 San Pedro: Stable in town; tours offline; top up data before Paso Jama.Days 15–17 Salta/Jujuy or Mendoza: Good urban 4G; rural patches are offline.Days 18–21 Buenos Aires: Strongest connectivity of the trip; clear your uploads and map downloads for the flight home.Partnering and stopover extrasHospitality and tour operators in the Andes: help your guests stay connected—explore co‑branded solutions via our Partner Hub.Transatlantic flyers: test your eSIM setup on a layover with an Esim United States or Esim Western Europe before hitting high-altitude blackspots.FAQs1) Do I need a local SIM in each country?No. A multi‑country eSIM covering Peru, Bolivia, Chile and Argentina is simpler and works well for a 3‑week pace. Consider a local SIM only if you’ll spend longer in one country and want the absolute best regional coverage.2) Will my WhatsApp number change with an eSIM?No. WhatsApp is tied to your registered number, not your data line. Keep your home SIM active for voice/SMS (roaming off if you wish), and use the eSIM for data—WhatsApp continues as normal.3) Can I hotspot to my laptop or camera?Yes. Enable tethering on your eSIM. Mind your data: cloud backups and OS updates can burn gigabytes—set them to Wi‑Fi only or schedule in big cities.4) What if there’s no signal on the Uyuni/Atacama legs?That’s expected. GPS still works offline. Pre-download maps and translations, carry a power bank, and sync plans with your tour operator before departure.5) Will I get roaming charges at borders?If you’re using a multi‑country eSIM with coverage in both countries, you won’t incur extra roaming fees from your home carrier. Keep roaming off on your home SIM to avoid accidental use.6) I’m connecting via Europe or the US—worth getting a layover eSIM?Yes. It’s an easy way to test your setup and stay reachable. Try Esim North America or country options like Esim Spain, Esim France, or Esim Italy for common hubs.Next step: Browse South America coverage options and build your plan on Destinations.

31 Oct 2025
Multi-Network Smart Switching: Rollout Notes & Supported Regions

Multi-Network Smart Switching: Rollout Notes & Supported Regions

Smart, seamless coverage shouldn’t be a lottery. Our new Multi-Network Smart Switching automatically connects your Simology eSIM to the best available partner network in your location, then re-evaluates in the background as conditions change. The result: fewer dead spots, more consistent speeds, and less time fiddling with settings. This post is your single source of truth for the simology smart switching rollout: what’s live today, what’s next, supported regions/carriers, device tips, and known limitations. If you manage travellers or teams, there’s guidance for you too.We’re rolling this out region by region to ensure quality and stability. As of publication, Smart Switching is standard across key Western Europe and North America destinations, with phased expansion underway elsewhere. You’ll find a clear changelog below, plus setup steps and practical pro tips gathered from early users. For the technical deep dive (how the selection engine weighs signal, latency and cost), see our note under “Tech explainers”.What is Multi-Network Smart Switching?Smart Switching lets a single eSIM session move across multiple local partner networks in a country (and across borders) without you manually changing carriers. Instead of relying on one roaming partner, your device is guided to the best option available based on real-world conditions.What you get versus a single-network eSIM: - Higher reliability in fringe or congested areas. - Better average speeds by steering to less-loaded networks. - Smoother cross-border transitions on regional passes. - Less manual intervention—no need to lock to one network.For a technical overview of how our selection engine works, partners and resellers can find deeper notes on the Partner Hub.Rollout at a glance (changelog)We’re sharing the rollout transparently so travellers and ops teams can plan confidently.October 2025General availability in Western Europe and North America regional products.Default-on for new eSIM activations in supported countries; existing eSIMs gain it after next profile refresh.September 2025Expanded beta to France, Italy, Spain and the United States; added live failover on 4G/5G.August 2025Closed beta in select Western Europe markets; early access for enterprise groups via For Business.Note: Capability depends on local partner integrations and device support. Check the live country list on Destinations before you fly.Supported regions and partner coverageCarrier availability can change; the lists below are indicative of current partners used for Smart Switching. You may see some or all of these networks in a given location. For the latest, refer to Destinations.Western Europe (general availability)France — typical partners include Orange, SFR, Bouygues. See country detail on Esim France.Italy — typical partners include TIM, Vodafone, WindTre. See Esim Italy.Spain — typical partners include Movistar, Orange, Vodafone. See Esim Spain.Germany — typical partners include Telekom (DT), Vodafone, O2.Netherlands — KPN, VodafoneZiggo, Odido (formerly T-Mobile NL).Belgium — Proximus, Orange, BASE.Switzerland — Swisscom, Sunrise, Salt.Austria — A1, Magenta, Drei.Portugal — MEO, NOS, Vodafone.Ireland — eir, Vodafone, Three.Regional bundles — Smart Switching across multiple countries on Esim Western Europe.North America (general availability)United States — typical partners include AT&T, T-Mobile, Verizon. See Esim United States.Canada — Rogers, Bell, Telus (varies by province).Mexico — Telcel, AT&T Mexico, Movistar.Regional bundles — multi-country coverage on Esim North America.UK and nearbyUnited Kingdom — EE, Vodafone, O2, Three.Channel Islands/Isle of Man — limited Smart Switching; coverage varies by island.Nordics & Baltics (expanding rollout)Sweden, Norway, Denmark, Finland — multi-network support across major operators; 5G availability varies.Estonia, Latvia, Lithuania — multi-network support in principal urban areas; expanding to rural zones.DACH & Benelux (general availability)Covered above under Western Europe; Smart Switching generally live across these markets.Central & Eastern Europe (phased)Poland, Czechia, Hungary, Romania, Croatia, Slovenia — multi-network live in tier-1 cities; rural expansion ongoing.APAC (pilot/early access)Australia, New Zealand, Singapore, Japan — Smart Switching available on selected plans; broader rollout planned following stability testing.Middle East & Africa (early access)UAE, Qatar, South Africa, Kenya — limited Smart Switching where multiple partner networks are available; more markets coming online in phases.Device compatibility and setupSmart Switching is a network-side feature that works best when your device is allowed to choose automatically.Supported devices - iPhone with iOS 16 or newer (recommended iOS 17+). - Android devices with eSIM support, Android 12 or newer (Pixel 6+, Samsung S21+ and newer, and equivalents). - Dual-SIM devices supported; set Simology as your Data SIM.How to enable (takes 2–3 minutes) 1) Update the Simology app to the latest version. 2) Install or refresh your eSIM profile as prompted in the app. 3) On your phone: - iPhone: Settings > Mobile Data > your Simology eSIM > Turn on Data, Data Roaming; ensure Network Selection is set to Automatic. - Android (Pixel example): Settings > Network & Internet > SIMs > your Simology eSIM > Enable Mobile Data, Roaming; ensure Automatically select network is on. 4) Leave 5G/LTE set to “Auto” and VoLTE enabled (where available). 5) If you previously manually locked to a network, toggle Airplane Mode off/on to clear the lock.Quick checklist before you travel - Install your eSIM while you have good Wi‑Fi. - Toggle Data Roaming on. - Set network selection to Automatic. - Ensure APN remains default (do not edit unless instructed by support). - Keep your device updated (carrier settings included).How Smart Switching decidesOur selection engine blends network-side signals and device feedback:Availability and signal quality (RSRP/RSRQ and SINR, where reported).Measured throughput and latency from lightweight probes.Congestion indicators (time-of-day patterns, historical performance).Local policy (e.g., prefer networks with better VoLTE/5G SA coverage).Power impact (avoid aggressive flapping; minimum dwell times apply).It’s designed to be conservative—fewer, smarter switches rather than constant hopping. If you need to hold a network temporarily (e.g., for a live upload in a strong cell), you can manually select it; Smart Switching resumes when you return to Automatic.For partner-facing logic and scoring weights, see the integration notes on Partner Hub.Benefits versus a single-network approachReliability: Better building penetration in one area? You’re steered there. A festival saturates a cell? We move you off it.Speed consistency: The “best” network changes by street and time; Smart Switching adapts without you intervening.Cross-border ease: On regional passes, your device hands over cleanly when you cross into the next country.Fewer support headaches: No more “try another network” back-and-forth—your eSIM tests options automatically.Traveller-first: Works quietly in the background; you focus on your trip.Pro tips from early travellersUse Airplane Mode as a soft reset: if speeds dip, toggle it for 10 seconds to force a quick re-evaluation.Keep 5G on Auto: forcing 5G-only can backfire in patchy areas; Auto lets us pick LTE when it’s faster.Don’t edit APN: custom APNs can break switching logic; stick with the default profile.Hotspotting: tethering works, but heavy hotspot sessions can delay switching while we protect session stability.VPNs: Smart Switching works fine with VPNs; if you see unusual latency, test briefly without the VPN to isolate issues.Border crossings: you may see “No Service” for 10–30 seconds while the device updates network credentials—this is normal.For teams and partnersBusiness rollouts: Admins can enable Smart Switching at account or group level, apply country policies, and review network experience metrics in dashboards. Learn more on For Business.Resellers/partners: API flags and webhooks are available for status, preferred network lists, and policy overrides. Documentation lives on the Partner Hub.Known limitations and workaroundsData-first: Simology eSIMs are data-only. For voice/SMS and emergency calling, keep a native line active on your device.Minimum dwell times: To avoid flapping, we wait a short period before switching again unless the current connection is unusable.Country variability: Some countries restrict multi-network roaming; Smart Switching may behave like single-network there.Older devices: Certain chipsets report incomplete metrics; switching still works but may be less dynamic.2G/3G sunsets: In markets where legacy networks are retired, voice fallback depends on VoLTE support on your primary line.Enterprise firewalls: If using strict VPNs or private DNS, allow our lightweight probing to ensure accurate performance reads.simology smart switching rollout: where to startIf you’re travelling in Western Europe or North America, Smart Switching is already included on current regional plans like Esim Western Europe and Esim North America, as well as popular single-country packs such as Esim France, Esim Italy, Esim Spain, and Esim United States. Outside these regions, check your specific country page on Destinations for live status.FAQQ: Does Smart Switching cost extra? A: No separate app fee. It’s included on most current regional and supported single-country eSIMs. Check your plan page on Destinations to confirm availability for your chosen country.Q: Can I force a specific network? A: Yes. You can manually select a network in device settings. We recommend returning to Automatic afterwards so Smart Switching can optimise as conditions change.Q: Will this drain my battery? A: No significant impact. We rely on network-side data and lightweight device probes, with minimum dwell times to avoid constant reselection.Q: Is 5G supported? A: Yes, where partner networks provide 5G. Smart Switching may choose LTE if it’s faster or more stable in your location.Q: How do I see which network I’m on? A: Your status bar shows the current network name. The Simology app also displays the active network and recent switches in the connection details.Q: Is it available on business accounts? A: Yes. Business admins can enable it per group or policy and review network experience analytics. See For Business for rollout options.Need help?Check your destination’s live status and supported carriers via Destinations.In the app, run “Connection Check” and follow any suggested fixes.If issues persist, share your location, device model, and a short description of what you see (e.g., “drops to 3G indoors in Lyon”) with support—we’ll review the network log and adjust policy if needed.Next stepPlanning a trip? See where Smart Switching is live and pick the right eSIM on Destinations.

30 Oct 2025
VoLTE & Wi‑Fi Calling Abroad: Make Calls Reliably on eSIM

VoLTE & Wi‑Fi Calling Abroad: Make Calls Reliably on eSIM

If you travel with an eSIM, two features determine whether your calls “just work”: VoLTE (Voice over LTE) and Wi‑Fi Calling (VoWiFi). Both let you place normal voice calls without falling back to old 3G/2G networks. That matters because many countries have retired 3G and some are winding down 2G; in the United States, for example, VoLTE is essential for voice. This guide explains how to set up and troubleshoot VoLTE and Wi‑Fi Calling abroad, especially when you’re using a data‑only travel eSIM and want your home number reachable. We’ll cover carrier prerequisites, dual‑SIM line selection, roaming toggles, and practical fixes for the common pitfalls travellers hit. If you only skim one section, make it the “Set‑up recipes” and the troubleshooting tree. For destination specifics and compatible plans, browse our regional eSIMs, including Esim United States, Esim Western Europe and Esim North America, or explore all Destinations.What VoLTE and Wi‑Fi Calling mean when you roamVoLTE: Your phone makes standard cellular calls over 4G/LTE (or 5G) networks using IMS. It’s required in markets where 3G is shut down (e.g., USA). Without VoLTE support on the visited network, calls may fail or drop.Wi‑Fi Calling (VoWiFi): Your carrier routes your normal phone number over any Wi‑Fi or mobile data connection. Abroad, this lets your home number ring even if you’ve disabled roaming on your home SIM. Think of it as “your number, over the internet”.How this plays with eSIM: - Most travel eSIMs are data‑only. You keep your home SIM for your number and use Wi‑Fi Calling over your eSIM’s data. - If you buy a local eSIM with voice, you’ll use VoLTE for direct cellular calling in country. Ensure that plan and your device are VoLTE‑enabled on the visited network.Pro tip: For the US, prioritise VoLTE‑capable devices and plans; see Esim United States. For multi‑country trips, check regional coverage like Esim Western Europe and Esim North America.Prerequisites: what must be true for calls to workBefore boarding, confirm the essentials based on how you’ll call.If you’ll keep your home number via Wi‑Fi Calling over a travel eSIM (most common)Your phone supports Wi‑Fi Calling and it’s enabled on your home carrier account.Your home carrier allows Wi‑Fi Calling while abroad. Many do; some restrict it by country or plan.You can receive an SMS while on Wi‑Fi (needed for banking/2FA). Some carriers only deliver SMS over cellular; check before you rely on it.Your travel eSIM provides a stable data connection (4G or better).You know how to set “Default Voice Line” (iPhone) or “Preferred SIM for Calls” (Android) to your home SIM.If you’ll use a local eSIM for voice via VoLTEThe eSIM plan includes voice service (many travel eSIMs are data‑only).Your phone supports VoLTE on the visited carrier’s bands.The eSIM/carrier has provisioned IMS/VoLTE on your line.You’ve enabled VoLTE in device settings and allowed voice roaming.For the US: No 3G fallback; without VoLTE your calls won’t work.Planning resources: - Country pages highlight network specifics and plan types: Destinations - Popular country packs with excellent LTE coverage: Esim France, Esim Italy, Esim SpainSet‑up recipes that just workRecipe A: Keep your home number alive with Wi‑Fi Calling over a data eSIMThis gives you cheap local data and your usual number for incoming/outgoing calls and SMS.iPhone (iOS 16/17): 1. Install and activate your travel eSIM. Confirm data works. 2. Settings > Mobile Data: - Mobile Data: select your Travel eSIM. - Turn on Data Roaming for the Travel eSIM. - For your Home SIM: keep Data Roaming OFF to avoid charges. 3. Tap Default Voice Line: set it to your Home SIM. 4. Wi‑Fi Calling: Settings > Phone > Wi‑Fi Calling > On (for Home SIM). If your carrier presents a terms screen, accept/verify. 5. Allow Mobile Data Switching: - Recommended: ON. iPhone will use data from your Travel eSIM to support calls on your Home SIM, without using home data roaming. - Safety check: keep “Data Roaming” on the Home SIM OFF, so switching cannot trigger paid roaming. 6. Make a test call with Wi‑Fi or strong 4G data. You should see “Wi‑Fi” or “Wi‑Fi Calling” in the status.Android (Pixel/Samsung/OnePlus – wording varies): 1. Install and activate your travel eSIM. Confirm data works. 2. Settings > Network & Internet > SIMs: - Mobile Data: Travel eSIM. - Data Roaming: ON for Travel eSIM; OFF for Home SIM. - Preferred SIM for Calls: Home SIM. 3. Wi‑Fi Calling: Settings > Wi‑Fi Calling > On for Home SIM. - Calling preference: Prefer Wi‑Fi (or Wi‑Fi preferred) if available. 4. Optional: “Use SIM data for calls on other SIM” or “Dual SIM data switching” ON, if available. It will use Travel eSIM data to sustain Home SIM calls. 5. Test an inbound and outbound call.Pro tips: - Keep the Phone app’s line selector visible before dialling so you don’t accidentally place a call on the travel eSIM. - If SMS over Wi‑Fi isn’t supported by your home carrier, briefly enable home SIM cellular (still with data roaming OFF) to receive 2FA codes.Recipe B: Use a local eSIM for native voice via VoLTEUse this if your eSIM includes minutes or you need a local number.All devices: 1. Confirm the eSIM plan includes voice. 2. Settings > Mobile/Cellular > enable VoLTE/4G Calling for that line. 3. Enable Voice Roaming if you plan to cross borders within the plan’s region (e.g., EU). 4. Network mode: 4G/5G Auto. Avoid 3G/2G‑only modes. 5. Place a test call. Check the status bar shows 4G/VoLTE during the call (not “3G/ H/ E”).If calls drop to 3G or fail: - Update carrier settings (iPhone prompt) or install the APN/IMS config provided. - Reboot; re‑insert eSIM if needed. - Manually select a different partner network in the same country.Country specifics and planningUnited States: 3G is shut down; VoLTE is mandatory for cellular calling. If your phone or plan doesn’t do VoLTE on the visited network, use Recipe A (Wi‑Fi Calling over data) as your fallback. See Esim United States.Canada, Mexico and USA trips: plan for cross‑border behaviour and partner networks. Check Esim North America.Western Europe: Broad VoLTE support and EU‑wide roaming on many plans. Recipe A works well for keeping your home number; Recipe B is easy if your eSIM includes voice. See Esim Western Europe.Popular single‑country picks with strong LTE: Esim France, Esim Italy, Esim Spain.Travelling as a team? Centralise setup guidance and plan choice via For Business or coordinate with your reseller through our Partner Hub.Troubleshooting tree: call fails or drops when abroadStart with your scenario and follow the checks in order.1) My home number doesn’t ring; I’m using a data eSIM - Is Wi‑Fi Calling enabled on the home SIM? Turn it on. - Can your device reach data? Open a web page; if not, fix data/APN first. - Carrier allows Wi‑Fi Calling abroad? If unsure, test on hotel Wi‑Fi; if it only works on your home ISP, your carrier may restrict it. - iPhone: Allow Mobile Data Switching ON; Home SIM Data Roaming OFF. - Android: Wi‑Fi Calling preference = Prefer Wi‑Fi; Dual SIM data switching ON (if available). - Still no joy: toggle Airplane Mode ON then enable Wi‑Fi only; try calling. If it now works, your carrier might prioritise Wi‑Fi Calling when cellular is off.2) Calls fail in the USA on a local SIM/eSIM - Confirm the line supports VoLTE on that network. - Device: VoLTE/4G Calling ON; network mode 4G/5G. - If calls drop to 3G or never connect, switch to a different partner network or use Recipe A as a fallback.3) I can call but SMS 2FA won’t arrive - Some carriers don’t deliver SMS over Wi‑Fi. Temporarily allow the home line to register on cellular (keep Data Roaming OFF) to receive codes. - Ask your bank to enable app‑based or email 2FA as a travel workaround.4) Calls use the wrong line - Set Default Voice Line (iPhone) or Preferred SIM for Calls (Android) to the correct SIM. - Before dialling, check the SIM selector in the Phone app; on iPhone, long‑press the call button to switch lines.5) Wi‑Fi Calling toggles are missing - Your carrier or device may not support it, or it’s not provisioned. Update carrier settings/OS, or contact your carrier to enable. - Some countries restrict VoIP/Wi‑Fi Calling; try a different network/Wi‑Fi.6) Audio is poor or calls drop on Wi‑Fi - Switch Wi‑Fi to 5 GHz, or move closer to the router. - Turn off VPN; some VPNs break IMS traffic. - Disable battery/data savers that restrict background data.Pro tips and gotchasPrefer Wi‑Fi Calling for long international calls. It uses your home plan’s domestic rates for many carriers, but always check your tariff.Avoid bill shock: keep Data Roaming OFF on your home SIM. You can still use Wi‑Fi Calling via the travel eSIM’s data if mobile data switching is enabled.In dual‑SIM mode, iPhone can show “Primary” and “Secondary”; rename them to “Home” and “Travel” so you don’t mis‑dial.Emergency calls: Wi‑Fi Calling may not route accurately abroad. Know the local emergency number and, where possible, place emergency calls over the local cellular network.US travellers: bring a VoLTE‑ready device. Older handsets that relied on 3G voice won’t work for calling.Business itineraries: standardise a setup playbook (Recipe A) for your team and test before departure. See For Business.FAQsQ: What’s the simplest way to keep my number when I use a travel eSIM? A: Use Wi‑Fi Calling on your home SIM over your travel eSIM’s data (Recipe A). Set your travel eSIM as the data line, keep data roaming off on the home SIM, and enable Wi‑Fi Calling.Q: Do all travel eSIMs support voice calls with VoLTE? A: Many travel eSIMs are data‑only. If you need native voice, choose an eSIM that explicitly includes minutes/voice and make sure VoLTE is supported in your destination.Q: Will Wi‑Fi Calling work in every country? A: Not always. Most carriers support it internationally, but some restrict usage by location or plan. A few countries and networks limit VoIP/Wi‑Fi Calling. Test on both Wi‑Fi and mobile data at your destination.Q: My SMS codes aren’t arriving while abroad. Why? A: Some carriers don’t deliver SMS over Wi‑Fi Calling. Temporarily register your home SIM on cellular (with data roaming off) to receive them, or switch to app‑based 2FA.Q: In the USA, my calls fail on a local SIM. What now? A: You likely need VoLTE on that network. Enable VoLTE/4G Calling, set network mode to 4G/5G, and try another partner network. If still failing, use Wi‑Fi Calling over your travel eSIM’s data as a fallback. See Esim United States.Q: How do I avoid using the wrong SIM for calls or data? A: Set your Default Voice Line/Preferred SIM for Calls to your chosen number, and your Mobile Data line to the travel eSIM. On iPhone, consider turning on “Allow Mobile Data Switching” with data roaming off on your home SIM to stay safe.The quick checklistsBefore you fly: - Update iOS/Android and carrier settings. - Confirm Wi‑Fi Calling is enabled on your home SIM and supported abroad. - Decide your calling method: Wi‑Fi Calling over data (Recipe A) or local voice via VoLTE (Recipe B). - Verify your device is VoLTE‑ready for the region (critical for the USA). - Save our destination links: Destinations, Esim Western Europe, Esim North America.On arrival: - Activate data on your travel eSIM; test browsing. - Set line selection: Data = Travel eSIM; Calls = Home SIM (if using Recipe A). - Enable Wi‑Fi Calling for the line you’ll use to call. - Place a short test call and send yourself a test SMS.Next step: choose the right regional plan and follow the setup recipe for your device. Start with Destinations to pick your eSIM for the country or region you’re visiting.

30 Oct 2025