Data roaming on a Thailand eSIM: when you need it
- Only if it will not start
- On for the eSIM line
- Off at home
The short answer
The eSIM runs on a Thai network, so data roaming is normally not needed: leave it off. If the eSIM line does not connect, turn data roaming on for the eSIM line and try again; that is the store's own guidance. Keep data roaming off on your home line.
Checked October 2, 2026
When to switch it on
The eSIM connects to a Thai network, one of AIS, TrueMove H or NT. When the line comes up and data flows, no switch is needed. When the line will not connect, enable data roaming on the eSIM line and retry: the store names this switch as the fix for a line that does not start.
Where the switches are
iPhone: Settings, Cellular, the eSIM line, then Data Roaming. Android: the SIM settings, pick the eSIM, then Roaming. Repeat on the home line and turn it off there.
If it fails (Data roaming)
When signal is there but no data flows, confirm the eSIM line is the mobile data line and that roaming is on for it. Then follow not connecting. These plans are prepaid, so the switch cannot put extra charges on your plan.
More help
Install your Thailand eSIM at home, before you fly
Scan the QR code from your order page at home on Wi-Fi, within 30 days of buying, and keep the line off until you land. How to install a Thailand eSIM.
Switch your Thailand eSIM on when you land
After landing in Thailand, switch the eSIM line on and choose it for mobile data. If data does not start, turn on data roaming for that line only.
Thailand eSIM not connecting: the checks, in order
Is your eSIM not working in Thailand? Check the line, mobile data and airplane mode, then data roaming, pick the network by hand, and write to support.
Thailand eSIM refunds: when you get your money back
When the eSIM does not work and we cannot fix it, the refund is full. A working eSIM is not refunded. How to ask, and where the money goes.
Can my phone take an eSIM? Check it before you buy
Dial *#06#: if your phone shows an EID, it has an eSIM. It must also be unlocked. Check your model before you buy a Thailand eSIM.
Still stuck?
Orders, QR codes and refunds are handled by VietSIM support. Write with the link to your order page and your phone model.
contact@vietsim.com