eSIM for Thailand: what you need to know

The networks and the coverage

Thailand has two large operators, AIS and True, after dtac merged into True. Both have solid 4G and 5G coverage in Bangkok, Chiang Mai, Phuket and Koh Samui, and work on smaller islands such as Koh Tao and Koh Lanta.

Where coverage thins out is in the northern mountains, in national parks and some way out to sea. If you are hiking around Pai or taking a longer boat trip, download maps offline first.

How much data do you need?

For a two-week trip, 5 GB is enough for most people. Maps, messaging, some social media and a few bookings rarely add up to more, assuming you use the hotel wifi.

Streaming video or tethering a laptop burns through it considerably faster. An hour of HD video is roughly 1.5 GB, so 10 or 20 GB is the more realistic level.

Practicalities on arrival

Install the eSIM at home and leave it. Validity only starts when it connects to a Thai network, so preparing well in advance costs you no days.

Once you land in Bangkok or Phuket: switch the line on, enable data roaming for it, and turn data off on your Swedish subscription. The connection usually finds the network within a minute of leaving flight mode.

Common questions

Do I need to register the eSIM with a passport in Thailand?

No. The identification requirement applies to local prepaid cards bought in the country. A travel eSIM bought in advance requires no registration.

Can I make calls with the travel eSIM?

No, it is data only. Call over WhatsApp, Messenger or FaceTime, or keep your Swedish number active for ordinary calls.

Does it work on Koh Phi Phi and Koh Tao?

Yes, both have mobile coverage in the inhabited parts. The signal can drop for a while during the boat crossing.