Best SIM Cards for Southeast Asia Backpacking (2026 Guide for Indian Travelers)
✅ Last verified on-the-ground: 2026-07-17
Last verified: 2026-07-22
Verified against official carrier pages (AIS, Viettel, Cellcard, Airalo) on 2026-07-22
Looking for the best sim card for sea? Pick the wrong SIM on day one in Bangkok or Ho Chi Minh and you spend the rest of the trip apologising to Google Maps. Indian backpackers who leave India on Airtel or Jio’s international roaming packs get a working phone, but the per-GB cost is brutal compared to buying a local tourist SIM at the airport. This guide covers what works across Thailand, Vietnam, Cambodia, Laos, Indonesia, Malaysia, Singapore, and the Philippines: which network to buy, where to buy it, what to expect to pay, and when an eSIM beats a physical card. For related planning, see our guide on Sea Backpacking Hub.
The short version: buy a local tourist SIM at the airport on arrival in your first country, top up locally as you cross borders, and only consider a regional SIM or eSIM if you’re hopping four or more countries in two weeks. Below is the country-by-country breakdown with real 2026 prices and the signal traps I tell every Indian traveller about before they fly.
Quick Answers
| What | Answer | Price (INR) |
|---|---|---|
| Cheapest way to stay connected across SE Asia | Buy a local tourist SIM at each country’s main airport on arrival | ₹855 (~299 THB or ~$8.87) for AIS in Thailand, ₹734 (~200,000 VND or ~$7.62) for Viettel in Vietnam |
| Best network in Thailand | AIS (also called 1-2-Call / AWN), best 4G/5G coverage nationwide | ₹855 (~299 THB or ~$8.87) for 8-day tourist pack |
| Best network in Vietnam | Viettel for rural and border coverage, Mobifone for city speeds | ₹734 (~200,000 VND or ~$7.62) for 30-day tourist pack |
| Best network in Cambodia | Cellcard or Smart, both run on the same cell towers in tourist areas | ₹482 (~5 USD) for 30 days |
| Easiest option if crossing 4+ countries in 2 weeks | Airalo or Nomad regional eSIM, buy before you fly | ₹2,408-₹3,854 (~25-40 USD) for 5-10 GB regional |
Subodh’s Pro Tip: Don’t trust the “unlimited data” sticker at the airport counter. Thailand’s AIS ₹855 (~299 THB or ~$8.87) pack is the rare case where it’s genuinely unlimited at full speed. Vietnam’s tourist SIMs advertise “unlimited” but throttle to 256 kbps after 3-4 GB per day, enough for maps and WhatsApp but useless for video calls. Always ask the counter staff: “After the high-speed quota, what’s the speed?”
Local SIMs vs. Regional SIMs vs. ESIMs: The 30-Second Decision
Three options, three different use cases:
Local tourist SIM: Bought at the airport of each country you land in. Cheapest per-GB. Requires you to swap physical SIMs at each border. Best for trips of 2+ weeks in 1-3 countries. Counter staff set it up for you in 5 minutes.
Regional SIM (physical): One physical SIM that works across multiple SE Asian countries. Convenient but expensive per-GB compared to local SIMs. Best for short trips hitting 4+ countries in under 10 days.
eSIM (Airalo, Nomad, Holafly, etc.): Digital SIM you download to your phone before you fly. No physical swap. Works across multiple countries on one plan. Best for travellers with eSIM-compatible phones (iPhone XS and later, most 2020+ Android flagships) who want zero friction at the airport. Data-only, no local phone number.
Airtel / Jio International Roaming from India: Easiest if you want your Indian number active the whole trip (useful for OTPs from Indian banks, UPI apps, IRCTC). The daily pack is ₹299-799/day depending on plan, and per-GB cost is roughly 5-10x a local tourist SIM. Only worth it for trips under 7 days where convenience beats cost.
For most Indian backpackers doing the standard Thailand-Vietnam-Cambodia-Laos loop over 3-4 weeks, the local SIM strategy wins. For island-hopping in Indonesia or the Philippines, a regional eSIM saves the headache of buying SIMs in smaller airports.
Country-by-Country Breakdown
Thailand: AIS, dtac, or TrueMove
Three main networks. AIS has the widest 4G/5G coverage including islands (Koh Samui, Koh Phangan, Koh Tao), and the strongest signal in rural north (Chiang Mai, Pai, Chiang Rai). Dtac runs a close second in Bangkok and the islands but drops signal in some border areas. TrueMove H is cheapest but coverage is patchy outside Bangkok, Phuket, and Chiang Mai.
The ₹855 (~299 THB or ~$8.87) 8-day unlimited pack from AIS at Suvarnabhumi or Don Mueang airport is the price-to-quality sweet spot. The same SKU at 7-Eleven inside the city is ₹57-₹86 (~20-30 THB or ~$0.59-$0.89) cheaper but requires you to register the SIM with your passport yourself. Read the dtac Thailand SIM guide for a full comparison.
For the islands specifically, the Thailand SIM in Koh Samui guide covers which network works on the ferries and at the beaches.
Vietnam: Viettel vs. Mobifone vs. Vinaphone
Three state-owned carriers, all using the same 4G towers in cities but with different coverage outside them. Viettel is the military network and has the best rural and border coverage (essential if you’re crossing into Laos at Tay Trang or taking sleeper buses through the central highlands). Mobifone has slightly faster speeds in Hanoi and Ho Chi Minh City. Vinaphone is the weakest of the three but the cheapest.
The standard tourist SIM at Noi Bai or Tan Son Nhat airport is ₹734-₹918 (~200,000-250,000 VND or ~$7.62-$9.53) for 30 days of “unlimited” data with a daily high-speed cap of 3-4 GB. Most Indians find Viettel the most reliable. Read the Vietnam SIM guide and the Viettel vs Mobifone vs Vinaphone comparison for full breakdowns. If you need OTPs from Indian banks or UPI apps, the Vietnam SIM with SMS guide covers which carrier reliably delivers Indian SMS. The how to top up Vietnam SIM guide covers recharging via app without a Vietnamese bank account.
If you’re only touching Vietnam’s Phu Quoc island, the Phu Quoc SIM guide covers the airport stall markup and where to get a fairer price in town.
Cambodia: Cellcard, Smart, or Metfone
Two strong networks. Cellcard and Smart both work well in Phnom Penh, Siem Reap, and the coastal towns. Metfone is a Vietnamese-owned carrier with slightly cheaper rates but weaker English-language support at the counter. For the Siem Reap airport specifically, read the Siem Reap airport SIM guide to know which counter is the airport markup trap.
The standard tourist pack is ₹482 (~5 USD) for 30 days with 10-15 GB of high-speed data, then throttled. Cellcard has slightly better signal inside Angkor Wat’s forest area, useful for mapping the temple complex offline.
Laos: Lao Telecom, Unitel, or Tplus
Laos is the SIM trap of SE Asia. Coverage drops sharply outside Vientiane, Luang Prabang, and Vang Vieng. On the slow boat from Huay Xai to Luang Prabang, signal is hit-or-miss for 2 days. Lao Telecom (Tplus) has the widest rural coverage. Unitel is slightly faster in Vientiane.
The standard pack is ₹215-₹430 (~50,000-100,000 LAK or ~$2.23-$4.46) for 30 days with 10-20 GB. Buy at Wattay Airport in Vientiane or at the immigration counter in Huay Xai (Mekong Riverside).
Indonesia (Bali, Java, Lombok, Sumatra): Telkomsel, XL, or Indosat
For Bali specifically, read the Bali SIM guide and the Indonesia SIM unlimited data guide. Telkomsel (the state carrier) has the widest 4G coverage across the archipelago including Lombok, the Gilis, and most of Bali’s interior. XL and Indosat are cheaper and slightly faster in Denpasar and Kuta but lose signal in Ubud’s rice fields and on the inter-island ferries.
The standard tourist pack at Ngurah Rai (Bali) airport is ₹807-₹1,614 (~150,000-300,000 IDR or ~$8.38-$16.75) for 30 days with 10-25 GB. Telkomsel’s tourist SIM is the same price as the local prepaid but includes free WhatsApp and a small international call allowance.
Malaysia: Maxis, Celcom, Digi, or Tune Talk
For full breakdown read the Malaysia SIM guide comparing Tune Talk vs Hotlink vs Celcom. Maxis (Hotlink) and Celcom have the strongest 4G/5G coverage including East Malaysia (Borneo). Tune Talk is a budget MVNO running on Celcom’s network, cheaper but with lower priority during congestion. Digi is the third option, mostly fine in cities and Penang.
For Indians flying into KLIA, buy at the airport Maxis/Hotlink counter (around ₹707-₹1,178 (~30-50 MYR or ~$7.34-$12.23) for 30 days with 30-50 GB). The 7-Eleven version is the same pack for ₹118-₹236 (~5-10 MYR or ~$1.22-$2.45) less but needs passport registration.
For pre-buy before flying from India, the Malaysia SIM online pre-buy guide covers Tune Talk and Celcom eSIM options.
Singapore: Singtel, StarHub, or M1 (and 7-Eleven SIMs)
Singapore is small and covered well by all three carriers. For budget travellers, the Singapore SIM guide covers Heya (Singtel’s budget brand), Pelago (StarHub’s tourist SIM), and the cheap 7-Eleven options like Singtel hi!Card and StarHub prepaid. Singapore also has free public WiFi almost everywhere, so most travellers use less mobile data here than anywhere else.
Prices run ₹746-₹1,865 (~10-25 SGD or ~$7.74-$19.36) for short-stay packs. The catch: you must register with your passport and the registration must be done at a Singtel/StarHub/M1 store or authorised reseller, not at the airport kiosk (those add a ₹963 (~10 USD)“activation” fee).
Philippines: Globe or Smart
Two networks locked in eternal competition. Smart has stronger signal outside Manila (Cebu, Palawan, Boracay, Bohol). Globe is slightly faster in Metro Manila. For full comparison read the Philippines SIM guide and the Philippine SIM number format guide for what those 09xx numbers mean.
Standard tourist pack is 100-300 PHP for 30 days with 8-15 GB. Buy at NAIA airport Manila or at the airport in Cebu.
Price Reference Table (SIM, INR)
| Country | Low (INR) | High (INR) |
|---|---|---|
| Thailand | ₹338 (~$3.51) | ₹855 (~$8.87) |
| Vietnam | ₹734 (~$7.62) | ₹918 (~$9.53) |
| Cambodia | ₹482 (~$5) | ₹482 (~$5) |
| Laos | ₹215 (~$2.23) | ₹430 (~$4.46) |
| Indonesia | ₹807 (~$8.38) | ₹1,614 (~$16.75) |
| Malaysia | ₹707 (~$7.34) | ₹1,178 (~$12.23) |
| Singapore | ₹746 (~$7.74) | ₹1,865 (~$19.36) |
| Philippines | ₹338 (~$3.51) | ₹855 (~$8.87) |
Where to Buy SIMs (and Where to Skip)
Airport kiosks in Thailand, Vietnam, Cambodia, Indonesia: These are the official carrier counters. Prices match the standard tourist packs. The staff are paid by the carrier, not by commission per sale, so they don’t upsell. Buy here on arrival.
Airport kiosks in Singapore and Malaysia: These are third-party resellers with a ₹482-₹1,445 (~5-15 USD) markup. Walk past them and go to the official carrier store 5 minutes from the arrivals hall, or wait until you reach the city.
7-Eleven and Circle K in Thailand: Cheaper than the airport, same official SIM, but you register the SIM yourself via the carrier app with passport photo. Takes 10-15 minutes. Worth it if you’re staying 5+ days in Thailand.
Online pre-buy before flying: Available for most SE Asian countries via Klook, KKday, or the carrier’s own website. Adds a small markup (₹193-₹482 (~2-5 USD)) but you land with a working SIM. Useful if your flight arrives late at night when airport counters are closed.
Street stalls in border towns: Avoid. Counterfeit SIMs, tourist-marked-up pricing, and no receipt. Stick to official carrier stores.
eSIM Option: When It Beats a Physical SIM
For Indians with eSIM-compatible phones who want zero friction, Get Nomad eSIM sells regional and single-country eSIMs you download before flying. Airalo, Holafly, and Ubigi are other eSIM providers in the same space.
When eSIM wins: Trips hitting 4+ countries in under 2 weeks, late-night arrivals when airport SIM counters are closed, dual-SIM phones where you want your Indian number active on the physical SIM for OTPs while using an eSIM for data.
When physical SIM wins: Trips over 2 weeks in 1-3 countries (cheaper per-GB), phones without eSIM support (older iPhones, budget Androids), travellers who need a local phone number for WhatsApp or Grab.
The regional eSIM trade-off: per-GB costs roughly 2-3x a local tourist SIM. If data is your top priority for the budget, physical local SIMs win. If convenience is the priority, eSIM wins.
FX Rate and What 1 INR Buys You in Mobile Data
At the time of writing:
- 1 THB = ₹2.87 (so ₹100 ≈ 35 THB)
- 1 VND = ₹0.0037 (so ₹100 ≈ 27,027 VND)
- 1 IDR = ₹0.0054 (so ₹100 ≈ 18,519 IDR)
- 1 USD = ₹96.53 (Cambodia prices)
For context, a 30-day high-speed 30 GB tourist SIM in Thailand costs roughly ₹860 (~$8.93), in Vietnam ₹740-₹925 (~$7.68-$9.60), in Bali ₹810-₹1,620 (~$8.41-$16.82), and in Cambodia ₹485 (~$5.03). Across a 4-country 4-week trip, expect to spend ₹3,000-₹4,500 (~$31.14-$46.71) on local SIMs total, which is still cheaper than 2 weeks of Airtel’s international roaming pack.
Common Mistakes Indian Travellers Make
Buying Airtel international roaming for the whole trip. Works, but ₹799/day × 14 days = ₹11,186, more than 3x the cost of local SIMs across multiple countries.
Not unlocking the phone before flying. Indian carrier-locked Jio and Airtel phones won’t accept foreign SIMs. Get before you fly (Jio gets you free after 90 days of usage, Airtel charges a small fee). BSNL phones are sometimes hardware-locked, check before you go.
Skipping the passport registration step. SE Asian tourist SIMs are tied to your passport. Lose the SIM and you can’t get it replaced. Photograph your SIM card and passport page, store in a cloud folder you can access from any device.
Assuming “unlimited” means unlimited. Every SE Asian “unlimited” SIM throttles after a daily quota. Ask the counter staff the exact post-throttle speed and daily cap.
Buying the wrong network in border regions. Laos, Cambodia, and Myanmar border areas have weak coverage from all carriers. Don’t rely on mobile data for navigation on the day of a border crossing. Download offline maps on hotel WiFi the night before.
Forgetting that some Indian apps block foreign IPs. UPI apps, IRCTC, and some banking apps may flag logins from a Thai or Vietnamese IP. Keep your Indian SIM active on roaming for the rare OTP, even if you use a local SIM for data.
Connectivity Beyond SIMs
Most SE Asian hostels and cafes have free WiFi, fast enough for video calls and uploads. Coworking spaces in Bangkok, Chiang Mai, Bali, and Ho Chi Minh City charge ₹500-1,500/day for high-speed fibre. Cambodia has the most unreliable public WiFi outside Phnom Penh and Siem Reap; read the Cambodia WiFi and power outage guide for what to expect.
For electronics beyond SIMs, read the electronics to bring from India guide and the SE Asia plug adapter guide. Thailand uses Type A/B/C/F plugs, Vietnam uses Type A/C/F, Indonesia mostly Type C/F, Malaysia and Singapore use Type G (British 3-pin, same as India’s older sockets). The EU plug vs Philippines guide covers Philippines-specific socket quirks. The best power banks for SE Asia guide covers airline limits and capacity choices. And if you’re wondering whether to swap your Indian electronics for cheaper buys abroad, the electronics cheaper in Cambodia guide covers the actual answer.
Subodh’s Take
Buy the local tourist SIM at your first airport. Don’t overthink it. The ₹200-₹500 (~$2.08-$5.19) you save by hunting for a regional eSIM deal will cost you 30 minutes of stress on day one when you can’t find your hostel. Spend those 30 minutes eating street food instead. The only time I break this rule is when I’m doing a 5-country sprint under 10 days or arriving past midnight at an airport where the SIM counter closes at 11 PM. For everyone else, local SIM, top up as you go, enjoy the trip.
FAQ
Which SIM has the best network across SE Asia?
No single SIM covers all 8 countries well. The closest option is a regional eSIM from Airalo or Nomad, but per-GB cost is 2-3x a local tourist SIM. For most trips, buying a local SIM in each country gives the best speed and price.
Should I keep my Indian SIM active on roaming?
Yes, for OTPs from Indian banks, UPI apps, and IRCTC. Indian SIMs on roaming cost ₹10-₹50 (~$0.10-$0.52) for incoming SMS, so the cost is minimal. Put your Indian SIM in SIM slot 1 for calls/SMS, use a local SIM or eSIM in slot 2 (or eSIM) for data.
Can I use my Indian eSIM-compatible phone abroad?
Yes, if it’s unlocked. Jio and Airtel phones sold in India from 2018 onwards are usually unlocked by default, but check before you fly. Carrier-locked phones reject foreign SIMs.
How much data do I need for a 4-week trip?
Around 30-50 GB total if you’re using hotel WiFi for video calls and uploads. Most travellers use 1-2 GB per day on maps, WhatsApp, Uber/Grab, and Instagram. Buy the local “unlimited” SIM and don’t worry about hitting caps.
Are airport SIM counters safe?
Yes, in Thailand, Vietnam, Cambodia, Indonesia, and the Philippines the airport counters are official carrier stores. Singapore and Malaysia airports have third-party resellers with a small markup; walk 5 minutes to the official store instead.
Do SE Asian SIMs work in border regions?
Coverage drops sharply within 5-10 km of most land borders. Download offline maps the night before any border crossing. Laos-Cambodia and Thailand-Myanmar borders have the weakest signal.
Will my UPI and Google Pay work abroad?
UPI works through international apps but most Indian merchants only support domestic UPI. Google Pay India doesn’t work outside India. Carry a forex card or some US dollars as backup. Keep your Indian SIM active for OTPs even if you use a local SIM for data.
