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 glance
Week 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 trip
For 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 notes
Cusco & 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 Copacabana
- Puno: 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‑step
The 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 changes
- Coverage 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 weeks
Typical 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/day
For 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 cues
- Days 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 extras
- Hospitality 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.
FAQs
1) 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.