When an eSIM is not working in Thailand, the cause is usually a phone setting, not the plan. Turn on data roaming for the travel line, make that line your mobile data line, and restart the phone. If the line still shows no service, check the carrier lock and contact your provider before you delete anything, because a deleted profile is usually not refundable.
The fixes below cover no service, connected but no internet, and slow data, plus what provider terms say about replacements and refunds.
Key takeaways
- Data roaming must be on for the travel eSIM line, even though you are on a local Thai network.
- The phone uses only one line for mobile data, so the travel eSIM has to be selected as that line.
- A carrier-locked phone cannot use a travel eSIM from another provider.
- Never delete the eSIM profile while troubleshooting. Deleted profiles are excluded from refunds in TonMobile's terms.
Quick checks in order
Most eSIM no service problems in Thailand clear up with five checks done in sequence. Each one rules out a cause before the next.
Confirm the travel line is on
Open the mobile or cellular settings and check that the travel eSIM line is switched on.
Turn on data roaming for that line
Open the travel line's own settings and switch data roaming on. This single toggle fixes more cases than any other step, as the next section explains.
Select the travel line for mobile data
Set the travel eSIM as the line that carries mobile data. If your home line is still selected, the phone tries to use it and may run up roaming charges.
Toggle airplane mode, then restart
Switch airplane mode on and off to force a fresh network search. If that does not help, restart the phone so it reloads the eSIM profile.
Check the network name in the status bar
Look for AIS, TrueMove H (True) or dtac on the travel line. A Thai network name with no data points to the roaming or data line setting, not to coverage.
Do not delete the eSIM
Removing the eSIM profile does not reset it. In most cases the profile cannot be reinstalled from the same QR code, and TonMobile's terms exclude deleted or wrongly installed profiles from refunds.
Turn on data roaming for the travel line
Data roaming is the setting that most often stops a travel eSIM from working in Thailand. A travel eSIM connects to Thai networks as a visiting line, so the phone treats it as roaming even though the network is local to you.
Travel eSIM
Both Apple's support page and a 2022 Kod.ru review of TonMobile state that data roaming must be on for the travel eSIM line. The toggle belongs to the travel line only. Your home line can keep roaming off, which protects you from home carrier charges.
- Data roaming on for the travel eSIM line.
- Data roaming off for the home line, if you want to avoid home carrier roaming charges.
- Mobile data switched on at the top level of the settings.
- Airplane mode off after you finish changing settings.
If you have set this up before your flight, you can recheck it on the plane before landing. Our guide on how to set up an eSIM before you fly to Thailand walks through the full install.
Select the travel eSIM as the data line
A phone with two active lines sends mobile data through only one of them. When the eSIM is connected but there is no internet, the wrong line is often selected for data.
iPhone
Apple confirms that two eSIMs can be active at once: the home number stays on for calls and texts while the travel eSIM carries data. Open SettingsMobile ServiceMobile Data and choose the travel line. On some regions and iOS versions the menu reads SettingsCellularCellular Data.
Turn off the option that lets the phone switch data between lines automatically if you want all data on the travel eSIM. Apple notes that the home line may still incur roaming charges if it is used.
Android
Android menus differ by maker, but the setting usually sits in the SIM manager or the connections section of Settings. Look for a mobile data or preferred data SIM option and choose the travel eSIM.
Symptom
No service
The travel line shows no network. Check that the line is on, data roaming is on, then restart.
Symptom
Connected but no internet
A Thai network name appears but pages do not load. Check the data line selection and the roaming toggle.
Symptom
Data works, then slows
Speeds drop later in the day. On an unlimited pass this is often the daily full-speed allowance running out.
Check for a carrier-locked phone
A carrier-locked phone accepts only the SIM or eSIM of the carrier that sold it. If your phone is locked, a travel eSIM from any other provider will not connect, whatever settings you change.
Apple states that an iPhone must not be carrier-locked to use a travel eSIM. Open SettingsGeneralAbout and look at the carrier lock row. "No SIM restrictions" means the iPhone has no carrier lock.
Apple also lists the iPhone XS, XS Max, XR and later models as eSIM-capable. On Android, the lock status is not shown in one standard place, so ask your home carrier directly.
Only your home carrier can lift the lock
A travel eSIM provider cannot remove a carrier lock. If you are already in Thailand with a locked phone, a local tourist SIM will hit the same lock, so contact your home carrier first.
If eSIM is not an option on your phone, compare the trade-offs in our guide to a Thailand tourist SIM vs an eSIM.
Slow speeds: allowances and network context
Slow data on a working eSIM usually comes from the plan's speed rules, not from a fault. Unlimited travel passes often give a daily allowance at full speed and then slow the line until the next day.
| Provider | What the provider lists for unlimited plans |
|---|---|
| TonMobile | 1 GB per day at full speed, then 512 kbps |
| Saily | 5 GB per day at full speed, then up to 1 Mbps (15-day pass) |
| Holafly | Fair usage slowdown possible; hotspot 500 MB per day |
If speeds drop at the same point each day, you have most likely used the full-speed allowance. A fixed-size plan avoids daily caps, and our guide on how much data you need for a Thailand trip helps you pick a size.
How the Thai networks compare
Thailand's three main networks are AIS, TrueMove H and dtac, according to Opensignal's August 2026 report (data April 1 to June 29, 2026). dtac led download speed at 41.1 Mbps, with AIS at 40.8 Mbps and TrueMove H at 38.7 Mbps.
TrueMove H led 5G availability at 90.2%, ahead of AIS at 87.9% and dtac at 87.2%. AIS scored highest for coverage experience at 8.9 out of 10. Average speeds are close, so a slow line is more often a plan limit or a weak spot than a weak network.
When to contact support, and what to do first
Contact your eSIM provider when the line still has no service after roaming, the data line and a restart have been checked. Keep the profile installed while you wait, because support can only fix a profile that still exists.
Before you message support
- Keep the eSIM profile installed on the phone.
- Note the order number and the plan you bought.
- Take a screenshot of the travel line settings showing roaming on.
- Note the network name shown, or "No service", and your location in Thailand.
- Connect to hotel or airport Wi-Fi so you can reply quickly.
Replacement and refund terms
TonMobile's terms list three refund cases: an unsupported device, the network being unavailable within declared coverage, and an unresolved delivery or data fault. Support may offer re-activation or a replacement eSIM instead of a refund.
The esim refund request must be made before the package expires and no later than 180 days after purchase. Refunds to cards take up to 14 calendar days, while electronic and crypto payments take up to 5 business days.
| Situation | Refund case in TonMobile's terms |
|---|---|
| Phone does not support eSIM | Yes |
| No network inside declared coverage | Yes |
| Delivery or data fault support cannot fix | Yes |
| Profile deleted or installed wrongly | No |
The terms also state that data starts being consumed when the eSIM is activated on a device. Other providers set their own rules.
How to avoid problems next time
Most landing-day eSIM problems can be prevented at home, on Wi-Fi, before you fly. A short routine before departure removes the common causes covered above.
- Check that the phone has no carrier lock and supports eSIM before you buy.
- Install the eSIM at home on Wi-Fi, since Apple's setup requires a Wi-Fi connection.
- Label the lines clearly, for example "Home" and "Thailand".
- Set data roaming on for the travel line and off for the home line.
- Save the provider's support contact and your order details offline.
- Save your Thailand Digital Arrival Card QR code offline as well, since you need it on arrival.
TonMobile, for example, allows activation within 180 days of purchase, and its app lets you install a plan in a few steps. For a longer trip, read our Thailand eSIM guide for long stays.
To compare providers side by side, see the Thailand eSIM rating and the methodology behind the scores. Unfamiliar terms are explained in the glossary, and the main Thailand eSIM guide covers the basics.
FAQ
Why is my eSIM not working in Thailand after landing?
The most common cause is data roaming switched off on the travel eSIM line. The phone treats the travel line as roaming on Thai networks, so the toggle must be on. Also check that the travel eSIM is selected as the mobile data line.
Why does my eSIM show connected but no internet in Thailand?
A Thai network name with no internet usually means the wrong line is set for mobile data or roaming is off on the travel line. Select the travel eSIM as the data line, turn roaming on, then toggle airplane mode.
Do I need data roaming on for a travel eSIM in Thailand?
Yes. Data roaming must be on for the travel eSIM line, as Apple's support page states. You can keep roaming off on your home line to avoid charges from your home carrier.
Will a travel eSIM work on a carrier-locked phone in Thailand?
No. A carrier-locked phone only accepts its own carrier's SIM or eSIM. On an iPhone, the carrier lock row under Settings, General, About should read "No SIM restrictions". Only your home carrier can remove the lock.
Why is my unlimited Thailand eSIM so slow?
Many unlimited passes slow down after a daily full-speed allowance. TonMobile lists 1 GB per day at full speed and then 512 kbps. Speed returns the next day, or you can switch to a fixed-size plan.
Can I get an eSIM refund if it does not work in Thailand?
It depends on the provider's terms. TonMobile refunds an unsupported device, no network within declared coverage, or an unresolved fault, if requested before expiry and within 180 days of purchase. Deleted or wrongly installed profiles are not refunded.