eSIM for Koh Tao
Koh Tao is the small, dive-focused island in the Gulf, the cheapest place in the world to get certified and a magnet for divers and backpackers. Coverage is good around Sairee Beach and Mae Haad, the main hubs, with AIS the most reliable network, while the dive sites offshore and the quiet east coast are where signal drops away.
An eSIM Thailand gives you access to the same plans in Koh Tao as in the rest of the country. 5 GB is generally enough for maps, messaging and social media, while video streaming and hotspot use require more data. The plans shown range from 3 to 50 GB and start at $3.90. They are fully refundable within 30 days provided the eSIM has not been used on a network at the destination. The activation link is sent by email after purchase.
Getting connected in Koh Tao
Koh Tao is reached only by ferry, most famously the overnight boat from Chumphon on the mainland, or the catamaran from Koh Samui and Koh Phangan. The overnight crossing loses signal for most of the way and returns as you approach Mae Haad pier at dawn. Mae Haad is the arrival hub and well covered, so you can sort your dive school and accommodation on arrival. Save your dive shop's contact offline before the crossing, since many arrange pier pickups.
Thailand eSIM plans
Prices in USD. Instant QR activation. Pick your data, land connected.
Coverage in Koh Tao
For a small island, Koh Tao is reasonably well connected where the people are. Sairee Beach, the long western strip packed with dive schools, bars and guesthouses, and Mae Haad, the main pier town, both have good 4G on both networks, best on AIS. Chalok Baan Kao in the south is covered too. The hilly, jungle-covered interior, the viewpoints and the quiet east-coast bays like Tanote and Hin Wong thin out, with AIS holding best. The dive sites offshore have no usable signal, and the long ferry crossings from the mainland lose signal in open water.
Best network here
AIS (most reliable on the island)
| Area | Best network | What to expect |
|---|---|---|
| Sairee Beach | AIS / True | The main strip; good coverage across the dive schools, bars and stays. |
| Mae Haad (pier town) | AIS / True | Arrival hub with reliable coverage and the island's main services. |
| Chalok Baan Kao (south) | AIS / True | Covered along the southern bay and its guesthouses. |
| Interior / viewpoints | AIS | Hilly and jungly; signal thins on the climbs, AIS holds best. |
| East-coast bays (Tanote, Hin Wong) | AIS | Quiet snorkel bays reached by rough tracks; AIS the only reliable network. |
| Dive sites / ferry crossing | AIS | No usable signal at the dive sites or in open water; AIS reconnects near the pier. |
Where to stay and connect in Koh Tao
Sairee Beach
The heart of the island, a long strip of dive schools, beach bars and budget stays with the best coverage. The default base for divers and backpackers.
Mae Haad
The pier town where ferries arrive, with reliable coverage, restaurants and the island's main services. Convenient and well connected.
Chalok Baan Kao
A quieter southern bay with a relaxed scene and decent coverage. A calmer base still within reach of the dive schools.
East coast (Tanote, Hin Wong)
Secluded snorkel bays reached by steep rough tracks. Coverage is patchy and AIS-only; choose for tranquillity and snorkelling over connectivity.
Staying online while you move
Getting around Koh Tao is by rented scooter, water taxi or songthaew, and the interior roads are steep and rough. Coverage is best along the west coast around Sairee and thins over the hills to the east-coast bays, where AIS holds. The crossings to reach the island are significant dead zones: the overnight ferry from Chumphon and the catamarans from Samui and Phangan all lose signal in open water. For dive days, the boats head to offshore sites with no coverage, so treat them as offline and arrange everything with your dive school in advance.
How much data in Koh Tao
A dive trip or backpacker stay on Koh Tao runs on 5 to 7 GB, mostly used around the well-covered west coast. Dive days are effectively offline regardless of plan, so there is no benefit buying extra data for them. Use the strong Sairee and Mae Haad connection to upload photos and arrange courses, and download offline maps for the rough tracks to the east-coast bays.
Apps worth having in Koh Tao
| App | Why it helps here |
|---|---|
| 12Go Asia | Book the overnight ferry from Chumphon and catamarans from Samui and Phangan. Download tickets before the crossing; the overnight boat is a dead zone. |
| Google Maps offline | Essential for the steep interior tracks to the east-coast bays, where signal drops and roads are rough. |
| LINE | Dive schools confirm courses and pier pickups over LINE. Save your shop's contact before the ferry. |
| PADI / dive apps | Log dives and review course material offline; useful since the dive sites have no signal. |
| Windy / AccuWeather | Check Gulf conditions before crossings and dives, especially in the October-December monsoon when ferries can be rough or cancelled. |
Practical data tips for Koh Tao
- Use an AIS-based eSIM; it is the most reliable network on this hilly island.
- Treat dive days and the overnight Chumphon ferry as offline; neither has usable signal.
- Base around Sairee or Mae Haad for the strongest, most convenient coverage.
- Download offline maps for the rough east-coast tracks to Tanote and Hin Wong bays.
Koh Tao eSIM FAQ
Is there mobile coverage on Koh Tao?
Yes, good around Sairee Beach and Mae Haad, the main hubs, best on AIS. The hilly interior and quiet east-coast bays thin out, and the dive sites offshore have no usable signal.
Which network is best on Koh Tao?
AIS. It is the most reliable network on this small, hilly island, particularly for the east-coast bays and the interior. An AIS-based eSIM is the safe choice.
Will I have signal on the overnight ferry to Koh Tao?
No, not for most of the crossing. The overnight boat from Chumphon loses signal in open water and it returns as you approach Mae Haad at dawn. Download everything and save your dive shop contact before boarding.
Is there signal at the dive sites?
No. The offshore dive sites have no usable coverage, so dive days are effectively offline. Arrange your course and pickups with your dive school in advance over LINE.
Is there signal on the east coast bays like Tanote?
Patchy. The secluded east-coast bays are reached by rough tracks and have AIS-only coverage that can drop. Download offline maps before heading over.
How much data do I need on Koh Tao?
5 to 7 GB covers a dive or backpacker stay. Dive days are offline regardless, so use the west-coast connection for uploads and arranging courses rather than buying extra data.
Planning your Thailand trip?
See the full Thailand eSIM guide: operators, coverage, real prices and the honest verdict.