Reliable mobile internet is essential on Koh Samui — for tourists and long-term residents alike. Three main operators cover the island: AIS, True Move H, and DTAC (now merged with True). Coverage is generally good, with some variation by area.

The Three Operators

  • AIS — market leader, best coverage including jungle and mountain areas, fastest 4G/5G per independent tests. More expensive but most stable.
  • True Move H — after the 2023 DTAC merger, largest user base in Thailand. Good coverage in tourist zones; cheaper unlimited plans than AIS.
  • DTAC / True — merged 2023; DTAC SIMs now run on True's network.

Tourist SIM Cards

  • AIS Tourist SIM 8 days / unlimited 1 Mbps + 100 min calls: from 299 THB
  • True Tourist SIM 15 days / 30 GB high-speed: from 299 THB
  • AIS Tourist SIM 30 days: from 599 THB

Available: Samui Airport on arrival, 7-Eleven, FamilyMart, operator stores.

Monthly Plans for Residents

AIS: from 250 THB/month (unlimited 1 Mbps + 60 min); from 350 THB/month (40 GB high speed + unlimited 1 Mbps); from 699 THB/month (unlimited 100 Mbps 5G).

True Move H: from 299 THB/month (30 GB + unlimited 1 Mbps); from 399 THB/month (70 GB); from 499 THB/month (unlimited max).

Prices are approximate — check current rates at operator stores or official websites.

SIM Registration

Since 2018, all Thai SIMs require passport registration at point of sale. Tourist SIMs sold at the airport are pre-registered — no extra steps needed.

Home Internet

  • AIS Fibre (FTTH): from 599 THB/month (100/50 Mbps); 1 Gbps tariff is higher. Covers most of Chaweng and Lamai.
  • True Move Fibre: similar pricing, broader coverage in Bo Phut and Nathon.
  • 4G/5G home router: ideal where fibre isn't available; 30–150 Mbps depending on location. Router cost from 800 THB; SIM plan from 350 THB/month.

Best Coverage Areas

Strongest 4G/5G: Chaweng, Lamai, Bo Phut, Mae Nam, Chaweng Noi, Nathon. Mountain interior and remote parts of Taling Ngam/Lipa Noi may have weaker signal — AIS is more reliable there.

Tips

  • Buy a SIM at the airport on arrival
  • Switch to a monthly plan at an official store for long-term stays
  • Check your exact area coverage with nperf or Opensignal apps
  • AIS for stability and coverage; True for price and data volume