Best eSIM for Thailand

The short answer

Buy a Thailand eSIM with a clear, named data cap — something in the 10–20 GB range with 7–30 day validity — and skip anything sold as "unlimited." In Thailand, "unlimited" almost always means "1–3 GB per day at full speed, then throttled to speeds you can’t actually use." If your trip includes islands (Phuket, Koh Samui, Koh Phangan, Koh Tao, Krabi, Phi Phi), prefer a plan that runs on the AIS network. AIS has historically had the strongest coverage outside of dense Bangkok. For Bangkok-only trips, TrueMove H or AIS are both fine.

That’s the answer. The rest of this post is why, plus the caveats we’d want a friend to tell us before they bought.

We sell Thailand eSIMs, so take this with the appropriate grain of salt — but we also wrote this because we got tired of "best eSIM" posts that don’t mention the throttle.

The three networks behind every Thailand eSIM

Almost every travel eSIM you buy for Thailand — ours included — runs on one of three mobile networks. The reseller brand on the box matters less than the underlying carrier.

AIS (Advanced Info Service)

The largest operator in Thailand and historically the one with the broadest non-urban coverage. If your itinerary touches islands, jungle, national parks, or anything north of Chiang Mai, AIS is the default safe choice. Most travel eSIMs that "feel" good in Thailand are AIS underneath.

TrueMove H

Strong urban and metro coverage — Bangkok, Pattaya, Phuket Town, Chiang Mai city. Fast 5G in the cities where 5G is deployed. Coverage on smaller islands and remote rural is thinner than AIS.

DTAC

In late 2023, DTAC and True merged into True Corporation. Both brands still sell SIMs and the networks are being consolidated, but for a 2026 traveler the practical effect is: if your eSIM is on DTAC, it’s effectively on the same network family as TrueMove H. Coverage profile is similar — strong urban, weaker remote.

NT (National Telecom)

The fourth, government-owned operator. It exists, but travel eSIMs almost never use it and you don’t need to think about it.

The takeaway: when you pick a plan, you’re really picking a network. AIS for island-heavy itineraries. TrueMove or DTAC for Bangkok-and-back. We try to surface the underlying network on every plan we sell because it matters more than the marketing.

The "unlimited" trap

This is the single most important thing to understand about Thailand eSIMs, and it’s why we wrote this post.

Almost every "Unlimited Thailand eSIM" you see advertised is not actually unlimited. The pattern, near-universal across providers and resellers, looks like this:

You get a daily "high-speed" allowance, usually somewhere between 1 GB and 3 GB.
After you hit that daily cap, the plan throttles — often to 128 kbps, sometimes 256 kbps, occasionally 512 kbps. To put that in perspective: 128 kbps is roughly dial-up. Loading Google Maps becomes painful. Uploading a single photo to Instagram takes minutes. Video calls don’t work. Even text-based WhatsApp can stall.
The throttle resets at midnight Thailand time (UTC+7), not 24 hours after you started using data.
The next day, you’re back to full speed for another 1–3 GB.

This is in the fine print, every time. The headline says "Unlimited 30 days." The footnote says "1.5 GB/day FUP" (FUP = Fair Use Policy). They are not lying, exactly, but they are leaning on the word "unlimited" doing very heavy lifting.

We don’t sell "unlimited" plans for Thailand that work this way without saying so on the product page itself, above the buy button, in plain English. If you see "unlimited" anywhere — ours or anyone else’s — find the fair-use clause before you buy.

If you actually want to use a lot of data — tethering a laptop, streaming, working remotely — a plan with a clear, named cap (say, 20 GB over 14 days at full speed the whole way) is almost always better than "unlimited" with a daily soft cap. You know what you’re getting.

Coverage caveats nobody else publishes

A few patches of Thailand where eSIM coverage routinely disappoints, regardless of carrier:

Ferries between islands. Signal drops mid-crossing — Koh Samui to Koh Phangan, Koh Phangan to Koh Tao, Phuket to Phi Phi. Plan for offline maps. AIS holds on slightly longer than the others on most routes but no carrier is reliable in the channel.
Koh Tao and the smaller Koh Phangan bays. Some bays (Haad Yuan, Bottle Beach) are boat-access only and the cell coverage matches — patchy, fine for messages, not fine for video calls.
Khao Sok National Park. The lake area and the floating bungalows have minimal-to-no cell coverage on any network. Don’t plan to work from there.
Parts of Isaan (northeast Thailand). Outside the provincial capitals, coverage is fine for voice and basic data but 5G is rare and rural pockets can be 3G-only.
Krabi off-road and the back roads to Railay. Railay itself is fine (it’s just across the bay from Ao Nang). The longtail boat ride to it is not.

The general rule for islands and remote areas: AIS first, TrueMove second, DTAC third. For everywhere a tourist actually sleeps and eats, any of the three are fine.

What to actually look for in a plan

Six things, roughly in order:

A clear data cap, not "unlimited." "15 GB over 14 days" tells you what you’re buying. "Unlimited" with a daily soft cap tells you nothing useful.
Validity that matches your trip. A 7-day plan for a 10-day trip means you buy a top-up or a second plan. A 30-day plan for a 5-day trip is money on the floor.
Hotspot / tethering enabled. Most travel eSIMs allow it, but a few don’t. If you’re tethering a laptop, check.
The underlying network. AIS for island-heavy. TrueMove/DTAC for cities. We surface this on every plan.
5G included (not just 4G). Most plans now include 5G where available, but it’s worth confirming.
Voice and SMS. Travel eSIMs are almost always data-only. That’s usually fine — you’ll use WhatsApp, iMessage, Line — but if you need a Thai phone number to receive an OTP from a Thai service (Grab signup, some bank apps), an eSIM won’t give you one. A physical Thai tourist SIM will.

Compatibility for short trips

Short tourist stays don’t require KYC for eSIMs sold abroad — you can buy one before you fly, install it, and have data the moment you land. Your phone needs to be eSIM-capable, which means roughly iPhone XS / XR (2018) and newer for Apple, and most Pixel / Samsung Galaxy flagships from 2020 onward for Android. iPhone 14 and newer sold in the US are eSIM-only — they don’t have a physical SIM tray, which makes this even easier.

If your phone is older than that, or it’s carrier-locked from a US carrier (rare for unlocked phones, common for financed ones from AT&T / T-Mobile / Verizon), eSIMs won’t work. The fallback: pick up a Thai tourist SIM at a 7-Eleven in town. There’s a 7-Eleven approximately every 300 meters in any Thai city. Airport SIM kiosks at BKK and DMK also still exist, but the line at 2 a.m. after a long-haul is genuinely awful.

The dual-SIM dance

The whole point of an eSIM for travel: you keep your home SIM active for 2FA codes, banking apps, and the occasional family call, and you use the Thailand eSIM for data. On iPhone, this is Settings → Cellular → Default Voice Line (home), Cellular Data (Thailand eSIM). Turn off "Allow Cellular Data Switching" so your phone doesn’t accidentally fall back to your home plan’s international roaming and bill you $15/MB.

Also: turn off data roaming on your home line entirely. Belt and suspenders.

How install works

If you’re on iPhone with iOS 17.4 or later, our preferred install path is a one-tap Apple Universal Link. After payment, you tap "Install on this iPhone" from the order confirmation and iOS handles the rest — the eSIM profile downloads and installs without you ever touching a QR code. It’s the cleanest install experience on Apple’s platform and it’s the one we built the product around.

If you’re on an older iPhone, an Android, or you want to install on a different device than the one you’re reading the email on, a QR code is generated for every order. Scan it from your phone’s camera or eSIM setup screen and follow the prompts.

Either way, the eSIM activates when it first connects to a Thai network — usually when you land and your phone comes off airplane mode. Validity countdown starts then, not when you buy. So feel free to buy a few days early.

If the eSIM doesn’t activate within 24 hours of fulfillment — provider hiccup, profile rejected, anything on our side — we’ll refund the order, no questions asked. That’s our 24-hour activation-failure policy and it’s on every order we fulfill.

What we’d actually buy

Two common Thailand trip shapes:

10-day trip: Bangkok + islands (e.g., 3 days Bangkok, 7 days Koh Samui / Koh Phangan)

15 GB over 14 days, AIS network. The extra few days of validity covers a layover or a flight delay. AIS because of the islands. 15 GB is enough for maps, messaging, social, occasional video, and tethering a laptop for an evening or two.

If you’re working remotely from the islands, bump to 20 GB or more — same plan structure, just a bigger cap.

7-day trip: Bangkok-only

10 GB over 7 days, TrueMove H or AIS. Either works. TrueMove is slightly faster in Bangkok proper; AIS is a touch more reliable on the Skytrain. We’d default to AIS if we didn’t care about marginal speed, TrueMove if we did.

3-day weekend in Phuket

5–10 GB over 7 days, AIS. Short trips usually want a small cap and the safety of AIS coverage at the beach.

These are the plans we’d buy for ourselves. Your usage may differ — if you stream Netflix on cellular, double everything.

When NOT to buy a Thailand eSIM

We sell these. We still think you shouldn’t buy one in three cases:

Long-term stay (6+ months). Walk into any 7-Eleven, AIS shop, or True shop, show your passport, and buy a real Thai prepaid SIM. You’ll get a Thai phone number (useful for Grab, banking, food delivery), better-priced top-ups, and access to local promotions that travel eSIMs can’t match.
Digital nomad on a monthly visa. Same answer. Thai monthly prepaid plans from AIS or True are very cheap and include far more data than any travel eSIM at comparable prices. A travel eSIM makes sense for the first few days while you settle in; switch to local after that.
Phone isn’t eSIM-capable. If your device doesn’t support eSIM, no travel eSIM will help. Get a physical tourist SIM at the airport (AIS Traveler SIM and TrueMove Tourist SIM both exist) or a 7-Eleven in town once the airport queue calms down.

Honest is in our name. If a Thai SIM is better for your situation, get a Thai SIM. We’d rather you come back for the next trip.

Heading to Thailand? Browse our Thailand eSIM plans — we surface the underlying network, the real data cap, and the fair-use policy on every plan, before you click buy.