Bangkok in July is hot. Like, step-outside-and-immediately-regret-it hot. But your phone signal? Solid across the city.
Thailand is one of the easiest countries to stay connected in. AIS and DTAC have excellent 4G coverage in Bangkok, Chiang Mai, Phuket, and most provincial towns. The question for most visitors isn't whether they'll have coverage - it's whether to bother with an eSIM or just buy a cheap local SIM at the airport.
eSIM vs local SIM in Thailand
A DTAC Happy Tourist SIM at Suvarnabhumi Airport costs around 299-399 baht (£7-9) for 15-30GB over 30 days. That's hard to beat on price. AIS Tourist SIM is similar and arguably has slightly better coverage outside Bangkok.
Where eSIM wins: if you're arriving at a smaller airport (Chiang Mai, Krabi, Koh Samui), the kiosks aren't always open or easy to find. If you're going straight from the airport to a meeting or activity, having your data sorted before you land saves time. And if Thailand is part of a multi-country Southeast Asia trip, a regional eSIM covering the whole itinerary avoids the SIM-swap faff at each border.
Coverage by area
Bangkok: excellent everywhere. BTS Skytrain stations and even some MRT underground sections have signal now.
Chiang Mai: great in the city. Decent in the surrounding mountains, though Doi Inthanon and remote trekking areas drop to 3G or nothing.
Phuket: solid across the whole island. The Patong beach area is saturated with signal. Phang Nga Bay tours mean you'll be on a boat without signal for chunks of the day - fine.
Ko Samui and Ko Pha Ngan: good coverage in main areas (Chaweng, Lamai, Haad Rin). The interior and north coast of Ko Pha Ngan can be patchy.
Ko Lipe: honestly, manage your expectations. It's improving but it's still a small remote island. Main beach areas have signal; anywhere else is hit and miss. Download offline maps before you leave the mainland.
How much data for Thailand?
For a two-week trip with Maps, WhatsApp, Instagram, and no streaming: 5GB is fine. 3GB works if you're disciplined about downloading offline maps and using café Wi-Fi for anything heavy. If you're posting content daily or doing video calls, go 10GB.
Honestly, the 3GB plan is adequate for most people who aren't heavy users. Skip the unlimited plan unless you're genuinely going to stream video nightly - you probably won't.
See current plans at /esim-in-thailand.
Traveling to Thailand?
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