Using an eSIM on Phi Phi, Koh Phangan, Koh Tao and Koh Lanta
Signal on an island changes from beach to inland spot to boat deck. Here is what to prepare before the ferry and what to do when the signal drops.
Quick answer
- A Thailand eSIM can work in many spots on the islands, but signal strength differs by beach, inland location and boat, and nobody can guarantee it everywhere. Check the coverage map of the network behind the plan and the notes on the plan page.
- Install the eSIM before the ferry while you still have Wi-Fi, download offline maps and save your bookings on the phone. The signal may drop in stretches during the crossing.
- If there is no signal, toggle airplane mode, check data roaming, then try choosing the network manually.
Island signal is not like mainland signal
Phi Phi, Koh Phangan, Koh Tao and Koh Lanta each have busy beaches, quiet coves, hills that block signal and boat routes in between. Mobile signal therefore changes with where you stand, even on the same island.
For that reason this guide does not state which network covers which island. That changes and differs by spot. The safer habit is to check the coverage map on the official site of the network behind your plan, and read the notes on the plan page.
Why the network behind the plan matters
A travel eSIM has no towers of its own. It attaches to a local partner network, so signal quality on an island depends on that network and where you are. The partner network name is shown on the plan page when it is listed.
If the plan supports several networks in the country, the phone may switch by itself according to signal. If it does not switch or the signal is lost, try choosing the network manually following our help page. Menu names differ by model.
Where signal tends to differ on an island
| Spot | What to expect | How to prepare |
|---|---|---|
| Main beaches and pier areas | Often busy, so speed can dip when crowds are heavy | Do important tasks outside peak hours |
| Small bays and hillside bungalows | Hills and trees may block signal | Ask the stay about Wi-Fi and download things in advance |
| Inland roads and viewpoints | There may be stretches with no signal | Use offline maps and tell someone your route |
| On ferries and speedboats | Signal drops mid-sea in stretches | Finish important tasks before departure |
This table is general guidance, not island-specific data
Install the eSIM before the ferry
Installing an eSIM needs internet to download the profile. If you try at the pier or on the boat, the install may fail for lack of signal. Install at home or at a hotel on the mainland while you have Wi-Fi, and switch it on once you are in Thailand.
- 1Check your phone supports eSIMUse our device checker, and confirm the phone is carrier-unlocked.
- 2Scan the QR from your email or order pageFollow the steps in the how-to-install guide while on Wi-Fi. If the email does not arrive, the QR is always on the order page.
- 3Set it as the cellular data line, but hold off switching it on if validity starts on first connectionWhen validity starts differs by plan. Check the plan page.
- 4Test it before you crossOnce in Thailand, switch it on and open a web page on the mainland to be sure it works before boarding.
During the crossing and dead zones
In open water between islands there can be stretches with no signal. That is normal and does not mean the eSIM is broken. Finish anything that needs data before the boat leaves: tell your stay you are on your way, share your location with whoever is meeting you, and open your tickets and bookings.
- Download ferry tickets, accommodation and activity bookings to the phone, or screenshot them.
- Save the phone numbers of your stay and the pier on the phone; you can call them from your main SIM if it has signal.
- Charge fully and carry a power bank, since the phone drains faster when it hunts for weak signal.
- Keep the phone in a waterproof pouch or dry bag on small boats.
Offline maps and bookings to save
Offline maps help a lot on islands with small roads and uneven signal. Download the map of each island while on Wi-Fi. Most map apps offer area downloads, but menu names differ by app and version, so try the download and check it opens with data off.
Beyond maps, save your accommodation address in Thai, the pier name, ferry times and contact numbers, in case you need to show them to a driver or staff.
Using a hotspot at the bungalow
Some island stays have slow Wi-Fi or none. Turning on a hotspot from the phone that holds the eSIM can serve a laptop or tablet, if the plan allows sharing. Check the plan page for the terms and read our hotspot guide. Shared data counts against the same plan allowance.
If you have no signal, what next
- 1Move and wait a momentStep to a more open spot, away from hills or thick walls, and wait a few minutes.
- 2Toggle airplane modeTurn airplane mode on for ten seconds, then off, so the phone searches for a network again.
- 3Check data roaming and the cellular data lineMake sure data roaming is on for the eSIM line and the eSIM is chosen as the cellular data line. See the guide on turning data roaming on and off.
- 4Choose the network manuallyTurn off automatic selection and try another network from the list, following our help page on manual network selection. Menu names vary by model.
- 5Use stay or café Wi-Fi in the meantime, and contact usIf it still fails, contact our support in Thai, English or Chinese with your order number.
Our eSIMs are data-only, with no phone number or SMS. For OTP codes or ordinary calls, keep your main SIM alongside.
Where to read more about Thailand eSIMs
If you are still deciding which plan suits an island trip, see our guide to SIM cards for tourists in Thailand and the article on Thailand eSIMs for longer trips. A comparison of carrier roaming and eSIM is in its own article. Current plans and prices are on the Thailand eSIM page.
Frequently asked questions
FAQ
Does a Thailand eSIM work on Phi Phi, Phangan, Tao and Lanta?+
It can work in many spots, but we do not guarantee every beach and corner. Signal depends on the network behind the plan and where you are. Check the network's coverage map and the plan page notes.
Should I install the eSIM at the pier or on the boat?+
Better not. Installing needs internet to download the profile, so install beforehand somewhere with stable Wi-Fi.
Why does the signal drop on the ferry?+
Open water may have no tower close enough. This is normal for sea travel, so finish important tasks before departure.
What if there is no signal at my bungalow?+
Move to a more open spot, toggle airplane mode, try choosing the network manually, and ask your stay about Wi-Fi. If it still fails, contact us.
Can this eSIM make calls or receive SMS?+
No, it is data-only. Use chat or internet calling apps instead, and use your main SIM for OTP codes.
Can I get a refund if I have not installed it?+
Yes. If you have not installed it, you can request a self-service refund within 14 days. Check the latest terms on the policy page.
Instagram and TikTok have no web share button, so we open your phone's share sheet or copy the link instead.