TL;DR
Thailand has three carriers travellers actually meet: AIS, TrueMove H, and DTAC. Most travel eSIMs ride AIS or TrueMove. Thailand is also the country where unlimited eSIMs make the most sense — coverage is excellent on islands, and you'll burn data on Grab, Foodpanda, Wise transfers, and live translation faster than you'd expect.
Our live catalog of Thailand plans right now:
How Thailand's networks compare
- AIS — the strongest network overall. Best 5G in Bangkok and Chiang Mai, deepest island coverage (Phuket, Krabi, Koh Samui, Koh Phangan). If your travel eSIM doesn't say which carrier, it's most likely AIS.
- TrueMove H — a strong second. Excellent in cities, weaker on remote islands. Often the cheapest option in eSIM catalogs.
- DTAC — fine in cities; we'd avoid it for island trips.
Unlike Japan, the gap between Thailand carriers narrows dramatically once you're in a major tourist area. For a Bangkok-only or Phuket-only trip, the cheapest live plan is usually the right call.
Coverage by destination
Bangkok
Full 5G across Sukhumvit, Sathorn, Silom, On Nut, Thonglor — anywhere a traveller would actually stay. BTS and MRT stations all have public Wi-Fi backup if your eSIM ever flakes. Don't overbuy; 5 GB is plenty for a week of city use.
Phuket + Krabi
AIS coverage is excellent across Patong, Karon, Kata, Kamala, Phuket Town. Krabi town and Ao Nang are equally well-covered. Where it gets interesting: long-tail boats to Koh Phi Phi or Koh Hong have spotty coverage mid-sea. Use the time to read.
Chiang Mai + Pai
Old city Chiang Mai has full coverage on all carriers. Doi Suthep and the suburbs are AIS-favourable. Pai is far enough north that DTAC drops noticeably; AIS or TrueMove only.
Koh Samui, Koh Phangan, Koh Tao
AIS dominates the islands. Resort areas have good coverage; deep-jungle bungalows on Phangan or hike-up viewpoints on Tao will go dark on any carrier.
Northern provinces (Chiang Rai, Mae Hong Son)
Cities are fine, mountain roads are not. Don't rely on data for navigation in remote north-Thailand; download offline maps before you go.
When unlimited beats metered for Thailand
This is where Thailand differs from, say, Japan: unlimited plans are usually worth it for trips longer than 5 days.
The reason: Thailand's day-to-day digital life is data-heavy in ways Western travellers aren't used to. Grab (ride-hail), LINE (messaging — everyone uses it), Foodpanda (food delivery), Wise (currency conversion), Google Translate camera mode (menus + signs), and Maps with live navigation. Add hostel-Wi-Fi-replacement video calls home, and 10 GB disappears in a long weekend.
Heuristic:
- Trip ≤ 5 days — buy 5–10 GB metered.
- Trip 6–14 days — buy unlimited (often only $5-10 more than the equivalent metered plan).
- Multi-month digital nomad — get a 30-day unlimited and re-up.
Island-hopping logistics
Two things that catch first-timers:
- Ferry rides between islands drop coverage entirely past 1–2 km offshore. Plan downloads and offline content before boarding.
- Some resorts in Koh Phangan and Koh Tao are far enough from cell towers that even a strong AIS plan will struggle. Resort Wi-Fi is then your real connectivity. Buy the data plan for travel and meals; expect resort Wi-Fi for evenings.
How to install + activate
Same playbook as Japan: buy → QR by email → scan on the same phone you'll travel with → install. The eSIM stays inert until you land in Thailand and connect to AIS/TrueMove for the first time.
For Thailand specifically, toggle airplane mode on and off after landing — sometimes the phone needs a nudge to register on the local carrier instead of trying to roam on your home SIM. Five-second fix that we see catch a lot of travellers.
Closing thought
The boring-but-correct Thailand pick: mid-tier AIS-backed unlimited plan, 14 days, install at home. Unlimited is the right call here more often than not, and AIS is the right carrier for almost every itinerary.
Or skip the calculus and let the concierge size it for you.