The three carriers
Thailand has three major mobile networks. AIS is the largest, with the broadest coverage including remote islands and northern villages, and the best 5G rollout in Bangkok and major cities. TrueMove H is the second-largest and competitive in urban areas, often with the most aggressive promotional pricing. DTAC merged with TrueMove operations recently and now functions as part of the True group, though it still markets separate plans. All three offer LTE coverage across 99%+ of populated areas.
Tourist SIMs at the airport
Suvarnabhumi and Don Mueang airports both have AIS, DTAC, and True counters in arrivals. Tourist packages are clearly displayed: typical options run 299 baht for 8 days with 15GB, 499 baht for 15 days with 30GB, and 599-799 baht for 30 days with 50-100GB. Calls and SMS within Thailand are usually included free or very cheap. Bring your passport — registration is required by law and takes about 5 minutes. Activation is instant.
Prices at city 7-Elevens or service shops are 50-100 baht cheaper than airport counters, but for the time saved arriving counter purchase is the easier choice.
Monthly local plans
For longer stays, monthly contract or prepaid plans are far better value. Typical postpaid plans run 299-499 baht per month for 30-50GB with unlimited social apps, and 599-799 baht per month for 100GB+ with 5G. Postpaid requires a Thai bank account or work permit; prepaid (refilled monthly) does not. Digital nomads on a 1-3 month stay usually buy a 30-day prepaid package then renew.
eSIM vs physical SIM
All three Thai carriers now support eSIM provisioning. Buy online, get a QR code, scan it, and you are connected within minutes — no shop visit needed. Travel eSIM apps like Airalo and Holafly also offer Thailand eSIM packages, often at higher prices than buying directly from a Thai carrier but with the convenience of activating before you land. Physical SIM is still slightly cheaper and removes any device compatibility concerns.
Topping up at 7-Eleven
Bangkok has roughly 13,000 7-Elevens, each capable of topping up any SIM. Walk in, give the cashier your number and the amount (50, 100, 200, 300, 500 baht common), pay cash or card, and the credit lands instantly. You can also top up via the carrier app (AIS Plus, DTAC App, TrueMove H) or at ATMs. Package activation (turning credit into a data package) is usually done by USSD code (e.g. *777# on AIS) or in the app.
Coverage and 5G
5G is widely available in Bangkok, Chiang Mai, Phuket, and Pattaya, with AIS leading the rollout. Speeds in 5G zones routinely hit 300-700 Mbps. LTE covers practically everywhere, including Koh Samet, Koh Tao, and rural Isaan villages. Truly remote areas (deep jungle parks, certain Andaman islands) may drop to 3G or have no signal — AIS is your best bet there. For most travelers staying within Bangkok and major destinations, all three carriers perform well.