Product info
Koh Samui eSIM plans
| Unlimited data · 5 days | $14.99 | Buy eSIM |
| Ohayu recommendsUnlimited data · 10 days | $30.99 | Buy eSIM |
| Unlimited data · 15 days | $34.99 | Buy eSIM |
| Unlimited data · 30 days | $43.99 | Buy eSIM |
| 3GB prepaid eSIM · 15 days | $4.99$1.66 / GB | Buy eSIM |
| 5GB prepaid eSIM · 30 days | $7.49$1.50 / GB | Buy eSIM |
| 10GB prepaid eSIM · 30 days | $9.49$0.95 / GB | Buy eSIM |
| 15GB prepaid eSIM · 60 days | $13.99$0.93 / GB | Buy eSIM |
| 20GB prepaid eSIM · 30 days | $17.49$0.87 / GB | Buy eSIM |
| 50GB prepaid eSIM · 90 days | $36.99$0.74 / GB | Buy eSIM |
You can install your eSIM before the trip and activate it when you arrive in Thailand. Validity starts after eSIM activation.
Plan details
How much mobile data you need
What's the best eSIM for Koh Samui?
A beach week – 3 GB
Maps, restaurants, boat trips.
Island-hopping – 10 GB
Two weeks, Samui, Phangan and Tao.
Thailand widely – 20 GB
Gulf islands plus Bangkok.
A longer stay – Unlimited
Tethering from a villa.
Coverage and network
Coverage ring road, hills and boats
Thailand mobile networks
Koh Samui is a ring road around a mountainous interior, and coverage follows the road. The developed north and east coasts are well served; the inland hills and the boat routes to the neighbouring islands are not.
Speedtest Global Index · Mobile · Thailand · June 2026
Download
137.04 Mbps
Upload
24.88 Mbps
Latency
20 ms
Global rank
#35 of 98
Koh Samui, specifically
- Chaweng, Lamai, Bophut: Reliable 4G and 5G along the main beaches and the ring road.
- The interior: The island's middle is jungle-covered hills with a few rough tracks. Coverage drops quickly off the ring road, and the waterfall roads are steep and unsigned.
- Ferries to Koh Phangan and Koh Tao: Signal fades in open water. Phangan is half an hour and Tao is a couple of hours - the latter goes properly offline mid-route.
- The Full Moon Party: On Koh Phangan, and it concentrates tens of thousands of people onto one beach. Networks there saturate on the night; agree where to meet.
- Ang Thong marine park: Day trips into the archipelago lose signal between the islands. The snorkelling stops have nothing.
All of Thailand
The plan covers the whole country, so Samui, Phangan, Tao, Bangkok and the Andaman coast all run on one eSIM.
How to install eSIM
Connected in 3 steps
- 01
Buy before you fly
Choose your data plan before your trip.
- 02
Download & install
Log in to your account, tap your eSIM, and follow the on-screen instructions.
- 03
Land & activate
Activate when you arrive in Thailand. Turn on roaming for the eSIM and it connects to a local network.
Before you buy, make sure your phone supports eSIM — see Ohayu compatible devices list or dial *#06#. It's a free request to your phone's settings. If you see the EID number — your phone is eSIM-compatible.
Arriving on Koh Samui
Samui airport, or the ferry
Samui's airport is privately run, open-air and unusually pleasant, with free terminal Wi-Fi. Flights into it are expensive, so many people fly to Surat Thani and take the bus-and-ferry combination instead - a much longer journey where data helps.
Side by side
Koh Samui eSIM Comparison
Indicative comparison based on publicly listed Thailand plans as of August 2026. Competitor pricing and policies change - check their sites for current terms.
Frequently asked questions
Where to buy a SIM card on Koh Samui?
Operator shops in Chaweng and at Central Festival, plus a counter at the airport. Thailand registers local lines against a passport. Island prices run above the mainland, as with most things here.
Do the island ferries keep coverage?
Partly. The half-hour hop to Koh Phangan holds a signal for much of the way; the two-hour run to Koh Tao does not. Ang Thong day trips go out of range entirely. Download what you need before boarding, and note the ferries cancel in rough weather.
Is there signal at the Full Moon Party?
Nominally, but it saturates. Tens of thousands of people on Haad Rin beach for one night is beyond what the local cells manage, and uploads will not go anywhere. Fix a meeting point and a time with whoever you are with before you go down to the beach.
eSIM not working on Koh Samui?
Inland off the ring road, or mid-crossing to Koh Tao, there is nothing in range. On the coast, make Ohayu the mobile data line, allow roaming, then cycle Airplane mode. Chat and support@ohayu.com are open 24/7.
