Thailand has three major mobile networks - AIS, TrueMove H, and dtac - and for most travellers AIS has the widest reach, especially on the islands and in rural areas, while TrueMove H and dtac are strong across cities and tourist hubs. A Thailand travel eSIM from eSIMpass starts at £2.49, and here is the part nobody explains clearly: a travel eSIM connects to ONE of these host networks, so you get that network's coverage. It does not scan all three and pick the strongest signal for you. This guide compares the three networks honestly, then tells you what an eSIM actually delivers so you buy with your eyes open.
Thailand's Three Networks at a Glance
Thailand's mobile market is a three-way split, and all three run modern 4G with expanding 5G in cities and major tourist areas:
- AIS (Advanced Info Service): The largest operator by subscribers and generally the widest footprint. AIS tends to have the strongest presence on the southern islands, in national parks, and in smaller mainland towns. If you are heading well off the Bangkok-Phuket-Chiang Mai axis, AIS is usually the network people recommend.
- TrueMove H: A close competitor with excellent city and tourist-zone coverage. Fast in Bangkok, Phuket, Pattaya, and Chiang Mai, and often praised for good speeds where the crowds are.
- dtac: Historically the value-focused operator, strong in urban centres and along the main routes travellers actually use. dtac now shares significant network infrastructure with TrueMove H following their corporate merger, which has improved its reach.
For a normal trip - Bangkok, a beach or two, some temples and street food - all three work well. The differences show up at the edges: remote islands, boat crossings, jungle treks, and small inland villages.
Thailand eSIM Plans and Pricing
| Data | Duration | Price |
|---|---|---|
| 1GB Data | 7 Days | £2.49 |
| 3GB Data | 30 Days | £3.17 |
| 5GB Data | 30 Days | £4.68 |
| 10GB Data | 30 Days | £7.40 |
| 20GB Data | 30 Days | £11.33 |
| 1 Day | 1 Day | £2.59 |
| 2 Days | 2 Days | £5.19 |
| 3 Days | 3 Days | £7.78 |
| 4 Days | 4 Days | £10.20 |
| 5 Days | 5 Days | £12.93 |
| 6 Days | 6 Days | £15.67 |
| 7 Days | 7 Days | £18.41 |
| 8 Days | 8 Days | £19.78 |
| 9 Days | 9 Days | £21.83 |
| 10 Days | 10 Days | £23.20 |
| 11 Days | 11 Days | £25.25 |
| 12 Days | 12 Days | £27.30 |
| 13 Days | 13 Days | £28.67 |
| 14 Days | 14 Days | £30.04 |
| 15 Days | 15 Days | £32.09 |
| 16 Days | 16 Days | £33.46 |
| 17 Days | 17 Days | £34.15 |
| 18 Days | 18 Days | £35.51 |
| 19 Days | 19 Days | £37.57 |
| 20 Days | 20 Days | £38.94 |
| 21 Days | 21 Days | £40.30 |
| 22 Days | 22 Days | £40.99 |
| 23 Days | 23 Days | £41.67 |
| 24 Days | 24 Days | £42.36 |
| 25 Days | 25 Days | £43.04 |
| 26 Days | 26 Days | £43.73 |
| 27 Days | 27 Days | £44.41 |
| 28 Days | 28 Days | £45.09 |
| 29 Days | 29 Days | £45.78 |
| 30 Days | 30 Days | £47.15 |
Every plan is prepaid and data-only, delivered as a QR code by email the moment you pay. There is no activation fee and no local phone number, which is fine for travel: maps, WhatsApp, Line, ride-hailing, and translation all run on data. You can install it before you fly and switch it on when you land at £2.49 value that undercuts airport SIM counters and roaming.
The Honest Truth: An eSIM Uses One Host Network
This is the single most important thing to understand, and most eSIM sellers gloss over it.
A travel eSIM is a roaming product. When you install it, your phone registers on one major Thai host network - the network that eSIMpass partners with for Thailand. You get that network's towers, that network's coverage map, and that network's speeds. What you do not get is a magic SIM that continuously tests AIS, TrueMove H, and dtac and hops to whichever is strongest in each village. That product does not exist for consumers, no matter how a listing is worded.
So when you read that "AIS has the best island coverage," that only helps you if your eSIM actually runs on the AIS network. If it runs on a different host, you get that host's coverage instead. Be skeptical of any provider claiming their eSIM "always connects to the best of all three networks" - that is marketing, not how roaming works.
What this means in practice:
- On a standard itinerary through cities and popular beaches, any of the three major hosts gives you solid, reliable data. The host choice barely matters.
- On a trip deep into remote islands or rural provinces, the host network matters more, because that is where the three networks genuinely differ.
- No single host, including AIS, has signal literally everywhere. Some spots have no coverage on any Thai network, which we cover below.
If you want the full breakdown of which plan fits which trip, see our best eSIM for Thailand guide.
Where All Three Networks Are Strong
The good news is that Thailand's tourist infrastructure is genuinely well covered. Expect reliable 4G, and 5G in many spots, across:
- Bangkok and its whole metro area, including Suvarnabhumi and Don Muang airports, malls, the BTS/MRT, and riverside districts.
- Phuket, Krabi, Ao Nang, and Pattaya - the big beach hubs have dense coverage right up to the sand.
- Chiang Mai and Chiang Rai in the north, including the old city and popular day-trip areas.
- Koh Samui, Koh Phangan, and Phuket's main towns - the developed islands have good service in and around the resort zones.
- Major highways, train lines, and the routes between big cities.
In all of these, the practical difference between AIS, TrueMove H, and dtac is small. You are choosing between "very good" and "very good."
Where Coverage Gets Patchy on Any Network
Here is the honesty that most guides skip. Thailand is a country of thousands of islands, mountains, and jungle, and some places have weak or zero signal on every network:
- Small and remote islands - Koh Kood, Koh Mak, Koh Rok, parts of the Similan and Surin islands, and far corners of the Andaman coast. Resort areas may have a bar or two; the far beaches often have nothing.
- Boats between islands - ferries and speedboats lose signal in open water. AIS often holds on slightly longer, but none reach mid-crossing.
- Jungle and mountain areas - Khao Sok, the deep national parks, and remote trekking routes around the north can be entirely offline.
- Some rural border provinces where towers are sparse.
The fix is the same regardless of which network your eSIM uses: download offline maps (Google Maps and Maps.me both let you save regions), screenshot your bookings and ferry tickets, and treat boat crossings and jungle days as offline time. This is a geography limitation, not an eSIM flaw.
eSIM vs Physical Thai SIM vs Roaming
eSIM vs Roaming vs Local SIM
Compare your options for Thailand
| eSIMpass | Roaming | Local SIM | |
|---|---|---|---|
| Setup time | Instant | None | 30-60 min |
| Cost per GB | ~$2-5 | $10-50+ | ~$3-8 |
| Surprise fees | None | Likely | Unlikely |
| Buy before trip | Yes | Yes | No |
| Keep your number | Yes | Yes | No |
| Speed | 4G/5G | 4G/5G | 4G/5G |
A few things worth knowing specifically for Thailand:
- Physical tourist SIMs require passport registration. Thailand mandates ID registration to buy a local SIM, so the airport counter takes a photo of your passport and fills out paperwork. An eSIM bought online skips that entirely - no queue, no passport handover, no paperwork.
- Roaming is the expensive trap. Leaving your home plan on can cost several dollars per day or more, and it is easy to forget it running in the background.
- A local SIM can be cheaper per GB if you are staying for weeks and do not mind the airport queue and registration. For most trips, the convenience of an eSIM wins.
Compare the numbers for your own plan with a travel eSIM versus your network's roaming rates.
How Much Data Do You Need?
- Light user (maps, messaging, occasional browsing): 1-3 GB for a week.
- Typical traveller (daily maps, social, photos, some video): 5-10 GB for one to two weeks.
- Heavy user or hotspot (streaming, video calls, sharing to a laptop): 15-20 GB or an unlimited-style plan.
Get a tailored estimate:
Setting Up Your Thailand eSIM
- Buy your Thailand plan and complete checkout
- Receive the QR code by email, instantly
- Install via Settings before you fly (needs Wi-Fi): add the eSIM and label it "Thailand"
- Land and switch on data roaming for the eSIM line - it registers on the Thai host network automatically
- Keep your home SIM in the phone for calls and texts if you like; data runs on the eSIM
Any iPhone from XR onward, Android flagships like Galaxy S20 and Pixel 3 and newer, and most recent eSIM-compatible devices will work. Full steps are in our installation and activation guide.
Frequently Asked Questions
Which Thai network is the best overall?
For raw geographic coverage, AIS generally leads, particularly on islands and in rural areas, with TrueMove H and dtac excellent across cities and tourist zones. But "best" depends on where you go - in Bangkok and the main beaches, all three are very good.
Can I choose AIS specifically for my eSIM?
A travel eSIM connects to whichever major Thai network eSIMpass partners with as the host, and you use that network's coverage. Consumer travel eSIMs do not let you hand-pick and switch between all three networks, and none auto-hop to the strongest of the three in real time.
Does the eSIM automatically pick the strongest of the three networks?
No. That is a common myth. Your eSIM runs on one host network. It gives you that network's signal, not a live blend of AIS, TrueMove H, and dtac. Any listing promising the "best of all three" is overselling how roaming works.
Do I need to register my passport for an eSIM?
No. Passport registration applies to physical tourist SIMs bought in Thailand. An eSIM is purchased online and skips that step, which is one of its biggest conveniences.
Will my eSIM work on the islands?
On developed islands like Phuket, Koh Samui, and Koh Phangan, yes, coverage is good in the resort areas. On small remote islands and during boat crossings, signal can drop to nothing on every network. Download offline maps before you set off.
Can I use the eSIM as a hotspot?
Yes, tethering works on the data plans, so you can share to a laptop or a travel companion's phone. Just watch your balance, since hotspot use consumes data quickly.
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