AIS vs True/dtac:
choosing your Thailand network

Thailand is effectively a two-carrier country

Thailand's mobile landscape changed dramatically in March 2023, when TrueMove H and dtac merged to form True Corp. The combined company now holds roughly 51–52% of the country's mobile subscribers — the largest base in the market. Its rival AIS remains the industry's revenue leader, serving around 46 million subscribers of its own.

For travelers, that simplifies things enormously. You don't need to memorize every brand on the shelf — the only question that matters is: does my plan connect to the AIS network, or to the True/dtac network? This guide covers what each network does best and which of the eSIM sellers we list rides which one.

What each network is good at

Both are nationwide carriers, but coverage guides and independent research point to different strengths.

"Wait — doesn't dtac still exist?" The merger, explained

This is where most of the confusion comes from. As a carrier, dtac was absorbed into True Corp in the 2023 merger. But as a brand, dtac is alive and well — most visibly in the "dtac Happy Tourist" SIM and eSIM line sold at airports and online. Seeing the dtac name doesn't mean you're buying a relic from a defunct company; it's a current product that connects to the merged True network.

Older blog posts still describe Thailand as a three-way choice between AIS, dtac, and True. Today the real structure is two groups. Buy a dtac-branded plan and, under the hood, you're on True/dtac.

One perk worth knowing: some dtac Happy Tourist plans zero-rate popular chat apps such as LINE and KakaoTalk, meaning messages and app calls don't count against your data allowance. If your group chat never sleeps, that's a real-world capacity bonus. The list of covered apps and conditions can change, so check the official site before buying.

Which of our listed sellers rides which network?

Sorting the Thailand plans we list by network, the picture looks like this (per our data at the time of listing):

• AIS official eSIM: the AIS network, naturally. Every plan includes a Thai number and a calling bonus.
• Airalo's dtac plans: the dtac brand — that is, the True/dtac network. The 50GB plan also includes 100 minutes of calls.
• Global sellers such as Holafly, Nomad, and Ubigi: many of these select the local network automatically. If your itinerary leans rural or island-heavy, choose a plan that explicitly states AIS support.

The network name is often buried in the plan details, so don't compare on price alone — check which network you'll actually be standing on. That's the single best way to avoid a bad surprise.

Four steps to decide by itinerary

1. Write down your routeBangkok and Pattaya only? Or Phuket, Koh Samui, and the hills north of Chiang Mai too? The answer changes everything.
2. City-only trips: either network worksBoth networks are fast in central Bangkok. If streaming and social media dominate your usage, True/dtac's Opensignal awards are a point in its favor.
3. Islands, outskirts, or mountains: lean AISWhen coverage is the deciding factor, pick a plan that connects to AIS — the AIS official eSIM being the obvious choice.
4. Check whether you need a Thai number, then buyRestaurant bookings and Grab verification are easier with a local number — look at plans that include one (all AIS official plans, Airalo's dtac 50GB, and others).

Frequently Asked Questions

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