Thailand — Read the full guide
A Thailand travel eSIM roams onto AIS or dtac. AIS reaches further on the islands and in the northern hills; dtac is solid across Bangkok and the main tourist strips. Install before you fly. Unlimited plans run full speed to a daily cap, then throttle — enough for Grab and maps, not for streaming.
The two networks diverge once you leave the mainland grid. AIS has the widest island and coastal reach: it is the more dependable choice on Koh Lanta, Koh Tao, the quieter side of Koh Phangan, and along the Andaman coast around Khao Lak. dtac performs well in Bangkok, Chiang Mai, Pattaya and the developed parts of Phuket and Samui, and is perfectly adequate if your trip stays on the well-worn route. For island-hopping or motorbiking in the north, a profile that can register on AIS is the safer bet.
Ferries and mountain roads are where people get caught out. The Surat Thani to Koh Tao crossing loses signal for long stretches in open water, and the same is true of the Krabi and Phuket island boats once they clear the headland. Khao Sok national park is patchy beyond the pier and the floating raft houses, and the Mae Hong Son loop north of Pai runs through valleys with nothing at all between villages. Cache offline maps for every leg, and screenshot your accommodation booking before you get on the boat.
This is one country where a local SIM is genuinely cheap, so the decision turns on convenience rather than money. AIS and dtac both run counters in the arrivals halls at Suvarnabhumi, Don Mueang and Phuket, and staff handle the paperwork in minutes with your passport. The catch is that those counters have real queues after a bank of arrivals, they are not always staffed on late-night flights, and Don Mueang's low-cost schedule produces exactly that. An eSIM that is already working when you switch off airplane mode skips the entire question.
Thai travel is app-heavy in a way that shows up in data use. Grab is essentially mandatory in Bangkok and runs a live map for every ride and every food delivery; LINE is how guesthouses, dive shops and drivers actually reach you; and Google Translate's camera mode gets constant use on street-food menus and pharmacy labels. None of it is heavy on its own, but together with photo uploads it adds up faster than travellers expect. Note that a data-only eSIM cannot receive the Thai SMS codes some banking and delivery apps demand.
Plans and prices
| Plan | Data | Validity | Price | Per GB | Daily cap | Hotspot |
|---|---|---|---|---|---|---|
| Unlimited · 1 day | Unlimited | 1 day | $2.95 | — | 500 MB/day, then 512 kbps | Included |
| 1 GB · 7 days | 1 GB | 7 days | $4.13 | $4.13 | No daily cap | Included |
| 3 GB · 15 days | 3 GB | 15 days | $10.03 | $3.34 | No daily cap | Included |
| 5 GB · 30 days | 5 GB | 30 days | $15.93 | $3.19 | No daily cap | Included |
| 50 GB · 10 days | 50 GB | 10 days | $47.14 | $0.94 | No daily cap | Included |
| 20 GB · 30 days | 20 GB | 30 days | $48.38 | $2.42 | No daily cap | Included |
Prices as of · Networks: TrueMove H, DTAC
When you land
Install the profile and scan the QR code at home over Wi-Fi before you board — doing it at Suvarnabhumi or Don Mueang means fighting congested airport Wi-Fi after a long flight. On landing, turn Data Roaming ON for the eSIM and leave your home line's data OFF; you should register on AIS or dtac within a couple of minutes.
Networks
AIS · dtac
Common questions
- Does an eSIM work in Thailand?
- Yes. Thailand has strong 4G and expanding 5G, and travel eSIMs roam onto AIS or dtac without any registration on your part. Your handset needs to be eSIM-capable and carrier-unlocked — worth confirming with your home operator before departure rather than at the gate.
- Do I need my passport to register a Thai eSIM?
- Not for a travel eSIM bought before you arrive. Thai SIM cards sold locally do require passport registration at the counter, which is quick but adds a queue. A roaming profile activated abroad has no such requirement, so you can walk straight through arrivals.
- Will it work on the islands and on ferries?
- On the islands, mostly yes near towns, beaches and piers. On ferries, expect to lose signal in open water, sometimes for the better part of an hour on the Koh Tao and Koh Lanta routes. Download your maps and booking confirmations before boarding rather than relying on service at sea.
- How much data do I need for two weeks in Thailand?
- Around a gigabyte a day covers most travellers. Grab, LINE, maps and messaging are all modest. What lifts it is uploading beach and dive photos, video calls home, and translate camera use at food stalls. If you plan to stream on long bus or train legs, size up rather than relying on the throttled tier.
- eSIM or a Thai SIM card from the airport — which is better?
- Local tourist SIMs are inexpensive and easy to get at Suvarnabhumi, Don Mueang and Phuket. The eSIM buys you time and certainty instead: no queue after a long flight, no counter that may be closed on a late arrival, and it is already connected before you reach immigration.
- Can I share the connection with my hotspot?
- Yes, tethering works on most Thailand plans, which is handy since guesthouse Wi-Fi in the islands is often weak and shared across the whole property. Bear in mind that hotspot traffic draws on the same daily allowance, and once you cross the full-speed cap, everything sharing the connection slows together.
- Does it come with a Thai phone number?
- No. Travel eSIMs for Thailand are almost always data-only. Calls and messages via LINE, WhatsApp or Messenger work fine, and Grab drivers can reach you in the app. But you cannot receive Thai SMS verification codes, which blocks some Thai banking apps and any service that insists on a local number.
Cities
Bangkok · Phuket · Chiang Mai
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