Thailand eSIM Guide: AIS, TrueMove H and Island Coverage
Thailand is one of the easiest countries to stay connected in. Coverage is strong in Bangkok, Chiang Mai, Phuket and the main islands. Ride-hailing apps make mobile data genuinely useful from the moment you land. The decision points are which network your plan uses, which matters most on smaller islands, and where your data exits, which affects some apps.
Which networks Thailand eSIMs use
Thailand's big mobile networks are AIS and TrueMove H. DTAC merged with True in 2023, but the DTAC brand and network are still in use. Among the wholesale Thailand plans we track:
| Plan type | Networks | Where data exits |
|---|---|---|
| Roaming via Singapore | AIS, DTAC, TrueMove H | Singapore |
| Roaming via Hong Kong | TrueMove H, DTAC | Hong Kong |
| Local breakout | TrueMove (4G) | Thailand |
Plans that can use more than one network give your phone a fallback when one network is weak, which is useful on islands and in national parks. If you'll spend most of the trip on Koh Tao, Koh Lipe or in the mountains around Pai, multi-network access counts for more than headline speed.
Coverage: cities, islands and the north
| Area | What to expect |
|---|---|
| Bangkok, Chiang Mai, Phuket town | Strong 4G and 5G |
| Popular islands (Samui, Phangan, Phi Phi) | Good around beaches and towns, weaker in the hills |
| Smaller islands and dive spots | Varies by island and network; boats lose signal offshore |
| Northern mountains (Pai, Doi Inthanon) | Gaps on winding roads and trails |
Ferries and long-tail boats often pass through dead zones between islands. Save ferry tickets and hotel confirmations as screenshots before you board.
Getting around with data
Ride-hailing apps such as Grab and Bolt operate in Bangkok and many tourist areas. They show the fare up front, which saves negotiating. Both may ask for a phone number to verify your account. Set them up at home, when your home number can receive the verification text easily.
Bangkok's BTS Skytrain and MRT stations generally have good coverage. Google Maps works well for public transport and walking directions throughout Thailand.
Routing: Hong Kong vs Singapore
Data that exits through Hong Kong or Singapore works fine for maps, messaging and social media. A few services restrict access from Hong Kong IP addresses. If an app you rely on behaves oddly, a plan that exits in Singapore or Thailand avoids the issue. The general trade-offs are explained in what a travel eSIM is.
How much data you'll need
| Trip | Suggested data |
|---|---|
| 5 days in Bangkok | 3 to 5 GB |
| 10 to 14 days, Bangkok plus islands | 10 GB |
| Digital nomad month in Chiang Mai | 20 GB or more, plus cafe and co-working Wi-Fi |
| Heavy video or hotspot use | A daily plan |
Beach days tend to mean lots of photo and video uploads. If your plan is small, upload over hotel Wi-Fi in the evening. The data guide has per-activity figures.
Combining Thailand with neighbouring countries
Thailand is often one leg of a longer Southeast Asia trip. Multi-country plans exist, but coverage lists differ: some include Thailand, Vietnam, Cambodia and Malaysia but not Singapore, for example. Check the country list before you buy. Our Vietnam guide covers the next most common stop.
Setting up and troubleshooting
Install the eSIM at home over Wi-Fi, keep the line switched off, and turn it on after landing at Suvarnabhumi, Don Mueang, Phuket or Chiang Mai. Set it as your cellular data line and enable data roaming for it. If it shows "No Service", try airplane mode, then manual network selection. The full checklist is in our troubleshooting guide.
Before you fly: a short checklist
- Confirm your phone is unlocked and supports eSIM. Phones bought on contract may need unlocking by your carrier first.
- Install the eSIM at home over Wi-Fi and leave the line off until you land.
- Save offline maps for Bangkok and any island you're visiting, plus screenshots of ferry and hotel bookings.
- Turn off photo backup over cellular if you're on a smaller plan. Beach photos and videos add up quickly.
- Pack a power bank. Heat, bright screens and constant map use drain batteries fast in Thailand.
FAQ
Do Thailand eSIMs include a Thai phone number?
Most travel eSIMs are data-only. Prepaid tourist SIM cards sold at Thai airports usually include a number, and they require your passport for registration.
Will my eSIM work on the islands?
On the popular islands, generally yes around beaches and towns. On small islands and boats, coverage varies, so a plan that can switch between networks helps.
Is an airport SIM better than an eSIM in Thailand?
Not necessarily. Airport SIMs give you a local number. A travel eSIM lets you skip the queue and keep your home SIM in the phone. See eSIM vs roaming vs pocket Wi-Fi for a full comparison.
Can I use Grab without a Thai number?
Usually yes. You can register with your home number, ideally at home before you travel, so the verification text arrives without roaming issues.
How do I know which network my eSIM is using?
On iPhone, the network name appears in Settings under the line's details or in Control Center. On Android, check the SIM or mobile network settings.