How to enable roaming on a Thai SIM card?

If you bought a new tourist or regular local SIM card, international roaming may be disabled on it by default. This means that as soon as you leave the country, even if you go to neighboring Laos, Vietnam, or Malaysia, your SIM card will not work at all, period. That is, you will not be able to receive SMS (they are free), receive calls (all will be chargeable), or of course make calls and use the internet. To make the card work, you just need to enable international roaming in advance. This is easy to do, here is how using the True operator as an example (which is actually Dtac):

You can enable international roaming through the operator's app (first, of course, you need to link your SIM card there), via USSD codes, or at a mobile phone shop. The easiest and most convenient way is through the app, where you can manage everything. Here are the instructions for True in screenshots:

If you don't want to install the app, the USSD request: *112*1#

When you enable roaming, it's better to immediately disable internet access with the operator; on the last screenshot, this is the Data Roaming button, it turns on automatically. Or via USSD: *113*2#

If you don't do this, you can accidentally go into negative balance instantly by opening a couple of pages or going into a messenger. To use the internet in countries neighboring Thailand, it's best to buy a local SIM or eSIM online. How and where to do this with links to profitable online stores, and where to buy a local SIM card in Thailand in general, which tariff to choose, and everything else in our full guide: How to buy a local Prepaid SIM card in Thailand: a complete guide to prices and tariffs

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