SIM Cards and Internet in Thailand: A Practical Guide

Who the operators actually are now#

The market consolidated hard. The True and dtac amalgamation completed on 1 March 2023, forming True Corporation Public Company Limited. As a condition of clearing the deal, the NBTC required the merged entity to keep serving customers under both brands for a period of years, so dtac still exists as a retail brand and still sells dtac-branded SIMs — but the underlying network was merged into a single radio access network, and there is now no meaningful coverage difference between a True SIM and a dtac SIM. Reporting has suggested the commercial brands could be consolidated from 2026; no formal retirement has been announced.

On the fixed side, AIS acquired 3BB (Triple T Broadband), with the NBTC board approving the takeover on 10 November 2023 subject to a five-year cap on broadband pricing. The combined business trades as AIS 3BB Fibre3 and is now the largest fixed-broadband provider in the country, ahead of TrueOnline, with state-owned NT a distant third.

The practical upshot for a new arrival is simple. There are two networks that matter. AIS has the better rural, island and geographic coverage; True has aggressive convergence bundles if you take mobile and fibre together, and claims broadly comparable 5G population coverage. Neither is a mistake.

Tourist SIM or local SIM?#

A tourist SIM is a pre-packaged bundle with a fixed validity, sold at the airport and in operator shops. You pay a premium for the convenience of walking away connected. True's published range prices the Tourist INFINITE SIM at ฿349 for five days, ฿449 for eight days and ฿699 for fifteen days, with a thirty-day dtac-branded equivalent at ฿1,199. AIS's tourist ladder is broadly similar; published third-party figures for AIS vary by a hundred baht or two between sources, so treat the exact number as approximate until you see it on the counter.

A local prepaid SIM is what residents use, and it is dramatically cheaper. The characteristic Thai product is unlimited data at a capped speed: roughly ฿200 buys unlimited data at 4 Mbps for two to four weeks depending on the operator and promotion, and long-stay bundles at around ฿2,700 for six months of unlimited 10 Mbps have been offered. Four megabits sounds derisory and is in fact perfectly adequate for maps, messaging, music and standard-definition video; it is not adequate for video calls, so most remote workers buy a higher tier or tether from fibre.

The dividing line is about three weeks. Below that, a tourist SIM is fine and the premium is trivial. Above it, buy a standard prepaid SIM and top it up. Each top-up typically extends validity by around thirty days, and the minimum top-up through a banking app is about ฿20.

Buying a SIM without being overcharged#

Home fibre: cheap, fast, and contract-shaped#

Thai fibre-to-the-home is close to universal in urban areas and priced accordingly. AIS 3BB Fibre3 publishes 300/300 Mbps at ฿499 a month on a twelve-month contract, 500/500 at ฿600 (or ฿500 on twenty-four months), 1 Gbps down / 500 Mbps up at ฿700 (฿600 on twenty-four months), and symmetrical 1 Gbps at ฿1,200. Installation is listed at ฿4,800 with an activation fee of ฿800, both routinely discounted or waived on a longer commitment. Prices are quoted excluding VAT, which catches people out.

TrueOnline prices 500/500 Mbps at ฿599 a month on twelve months, 1000/500 with a Netflix bundle at ฿999 on twenty-four months — dropping to ฿799 for existing True or dtac mobile customers — and a symmetrical 1 Gbps 'Fiber to Room' product at ฿899. The convergence discount is real and worth engineering your mobile choice around if you are taking both. NT is cheaper still in places but its English-language customer journey is poor and we could verify only a single current price point.

Twelve months is the entry-level commitment; twenty-four months is what actually buys the advertised headline price and the installation waiver. Read the early-termination clause before signing if your visa situation is not settled.

What speeds you should actually expect#

On Ookla's Speedtest Global Index using late-2025 data, Thailand's median fixed broadband download sits at roughly 270–275 Mbps, placing it somewhere in the global top ten to fifteen depending on the month. Uploads are near-symmetrical, which is unusual and is the reason Thailand is a genuinely good place to do video-heavy remote work. Median mobile download is around 135 Mbps, ranking somewhere in the high twenties to high thirties globally. Ranks move month to month; the magnitudes are stable.

Real-world mobile throughput is lower than the median suggests once you leave the cities: expect 50–150 Mbps along Bangkok's BTS and MRT corridors, 30–100 Mbps in central Chiang Mai and Phuket, and solid 4G rather than reliable 5G across most island and rural areas.

On coverage specifically, Opensignal's Thailand report published in June 2025 gave AIS the Coverage Experience award at 8.5, a full point ahead of dtac and TrueMove H on 7.4 each. That gap is where the practical advice comes from: if you spend significant time on the Gulf and Andaman islands, on ferries, or on mountain roads, take AIS. In Bangkok and the major cities the difference is not worth thinking about, and True's convergence pricing may well win.

Common questions#