Does a travel eSIM work on Thai islands?

Yes. A travel eSIM roams on AIS or True, the same networks a local SIM uses, so Koh Samui, Phuket and Krabi all work. Expect 4G rather than 5G at quieter beaches, and a gap in the middle of longer ferry crossings.

Is 5G available across Thailand?

No. 5G covers Bangkok, Chiang Mai, Pattaya, Phuket town and other urban areas well, but rural provinces, national parks and small islands are still 4G. That is enough for navigation, ride-hailing and streaming.

Is data fast enough for video calls in Thailand?

Yes. Even our slowest island reading of about 10 Mbps handled a stable HD video call, and city 5G was far above what any call needs.

Thailand eSIM speed test: what we measured in Bangkok, Chiang Mai and the islands

Wat Arun temple on the Chao Phraya river in Bangkok at golden hour — Bangkok's riverside is one of the fastest 5G areas we tested in Thailand.

Short answer · ≈72 Mbps national median

Thailand is fast where tourists actually spend time. Bangkok, Chiang Mai and Phuket town all carry wide 5G at 90–250 Mbps, while island beaches and long-tail boat piers fall back to 4G at 20–60 Mbps — still fine for maps, Grab and video calls. The weakest spots were ferry crossings and national parks.

How we tested: Speedtest by Ookla on a phone using a traverrsim eSIM, three runs per location, median reported, outdoors unless stated. Your own numbers vary with crowds, weather and handset — run the same test on arrival and compare.

Results by location

Mobile data speed test results at Thailand tourist locations
Location	Network	Download	Upload	Ping
Bangkok — Sukhumvit / SiamCity centreFastest readings in the country; BTS platforms included.	5G	180–260 Mbps	30–55 Mbps	22 ms
Bangkok — Wat Arun / Chao PhrayaRiversideStrong on both banks and on the cross-river ferry.	5G	120–200 Mbps	25–40 Mbps	25 ms
Chatuchak Weekend MarketBangkokCrowds knock the peaks down at midday.	5G	60–120 Mbps	15–30 Mbps	30 ms
Chiang Mai Old CityTha Phae GateConsistent across the moat and Nimman.	5G	90–160 Mbps	20–35 Mbps	26 ms
Doi SuthepMountain temple4G on the road up; patchy in the forest curves.	4G	25–55 Mbps	8–18 Mbps	38 ms
Phuket — PatongBeach road5G along the beachfront, 4G in the back sois.	5G	80–150 Mbps	18–32 Mbps	28 ms
Phi Phi / longtail boatsKrabi coastSignal drops mid-crossing — download maps first.	4G	10–35 Mbps	5–12 Mbps	48 ms
Koh Samui — ChawengMain beach strip5G near the town centre, 4G at quieter bays.	4G/5G	40–110 Mbps	12–28 Mbps	32 ms
AyutthayaHistorical parkReliable everywhere around the ruins.	4G	35–70 Mbps	10–20 Mbps	34 ms
Suvarnabhumi AirportArrivals halleSIM activates before you reach immigration.	5G	150–240 Mbps	30–50 Mbps	21 ms

Frequently asked questions

Does a travel eSIM work on Thai islands?: YesA travel eSIM roams on AIS or True, the same networks a local SIM uses, so Koh Samui, Phuket and Krabi all work. Expect 4G rather than 5G at quieter beaches, and a gap in the middle of longer ferry crossings.
Is 5G available across Thailand?: No5G covers Bangkok, Chiang Mai, Pattaya, Phuket town and other urban areas well, but rural provinces, national parks and small islands are still 4G. That is enough for navigation, ride-hailing and streaming.
Is data fast enough for video calls in Thailand?: YesEven our slowest island reading of about 10 Mbps handled a stable HD video call, and city 5G was far above what any call needs.

Other speed tests

Last updated 2026-08-19