Best eSIM for Thailand: Networks, Data and What to Check

The best eSIM for Thailand is not a brand but a combination: a plan that runs on the right local network for your route, with enough daily data and plan terms that are clear about hotspot, validity and throttling. For a city-only trip almost any mainstream network will do. For islands, ferries and the mountain north, the host network matters far more than the label on the plan.

Travel eSIM sellers do not own towers. Each plan connects to a Thai network behind the scenes, usually AIS or True/dtac, and two plans from the same seller can use different hosts. That is why the plan page deserves a careful read before you pay.

Which Thai network is best for a tourist: AIS, True or dtac?

AIS is the usual pick when your trip leaves the big cities. It generally gets the best reviews for coverage in rural areas, and independent testers have ranked it highly for consistency. True and dtac merged at corporate level in 2023 and are still integrating their networks, so for travellers they are best treated as one family. They are perfectly good in Bangkok, Chiang Mai city, Phuket's resort areas and most large towns.

Rankings shift between test rounds and sit alongside methodology you cannot see from a plan page. Treat them as a tilt, not a guarantee. If a seller does not say which network a plan uses, that is information in itself.

What about islands and the north?

Island coverage varies from island to island, and it drops away once you leave the main resort strip. Koh Samui and Phuket are well served in the developed areas. Smaller islands, quiet beaches and ferry crossings are where signal gets patchy, and where AIS is the more common recommendation.

The north works the same way. Around Pai, Mae Hong Son and the mountain roads, signal can vanish between valleys whichever network you choose. Download offline maps for the Google Maps area before any long drive, and do it on hotel Wi-Fi.

Does an eSIM give me 5G and a hotspot?

Both are plan features, not automatic. 5G needs a compatible phone, a plan that allows it and a spot with 5G coverage, which in practice means cities and busy tourist areas. Many travellers will spend most of their time on 4G and never notice.

Hotspot (tethering) is where plans differ most. Some allow it freely, some restrict it, and some do not mention it at all. If you plan to work from a laptop, look for a clear statement on the plan page. If it is silent, assume you should check before buying.

How many GB per day do I need in Thailand?

Light use is lighter than most people expect. Rough, commonly quoted figures:

• Google Maps navigation: around 10 to 20 MB per hour, and close to nothing with offline maps.
• Grab or Bolt rides: a few MB per ride.
• Messaging and photos: small, unless you send videos.
• Video calls: several hundred MB per half hour.
• Streaming video in HD: a couple of GB per hour, the real data hog.

A traveller who navigates, books rides and messages will usually stay well under 1 GB a day. Posting lots of photos and video pushes that up. Remote workers who hotspot a laptop and take video calls can use several GB a day. These are estimates and vary with app settings, so use them to size a plan, not to cut it fine. If you stream, save it for hotel Wi-Fi.

What should the plan page tell me before I buy?

Read these before paying, in this order:

1. Host network: AIS, True/dtac, or unspecified.
2. Data allowance and whether it is per day or total.
3. Validity: when the clock starts, at purchase, at install or at first connection to a network.
4. Throttling: what happens after a daily cap, and whether speeds drop or data stops.
5. Hotspot: allowed, limited or not mentioned.
6. Data only or not: MochiSim plans, like most travel eSIMs, carry data but no Thai phone number.

The validity start is the one people miss. If the clock starts on first connection, you can install ahead of the flight and lose nothing. If it starts at install or purchase, wait until closer to departure.

Will an eSIM work for Grab, LINE and bank apps without a Thai number?

A data-only eSIM gives you internet, not a phone number, calls or SMS. Many apps send a code by text during sign-up or login, and that is where travellers get stuck. Maps, messaging apps you already use and most booking apps work fine over data alone. For services that verify by SMS, such as ride-hailing, LINE or your bank, the dual-SIM approach covers it: keep your home SIM active for texts and let the eSIM handle data.

Set up and log in to the apps you need before you fly, while your home number still works normally. Check roaming charges on your home plan for receiving texts, since that is billed by your home provider, not by the eSIM.

How do I stay connected in Thailand with an eSIM?

Run through this phone checklist first:

• Your phone supports eSIM.
• It is carrier-unlocked.
• The software is up to date.

Install the eSIM at home on Wi-Fi, but keep it switched off until you land if the validity clock starts on first connection. In your phone settings, set the travel eSIM as the line for mobile data and leave your home SIM on for SMS, with data roaming turned off on the home line. Turn data roaming on for the eSIM line, as many plans need it. Screenshot the QR code and setup details in case you need to reinstall.