eSIM, local SIM or pocket wifi in Bangkok: which to pick

Every arrivals guide gives you the same three answers — buy a SIM, install an eSIM, or rent a pocket wifi — and none of them tell you which is right for you. The honest version is short: for most trips a travel eSIM is the easy button, a physical Thai SIM is worth it only when you need a local phone number, and pocket wifi has quietly become the wrong answer for almost everyone. Here is how to tell which case you are in.

The one question that decides it: do you need a Thai phone number?

Almost all the confusion around SIMs and eSIMs disappears once you separate two different things: mobile data and a Thai phone number. Nearly every option gives you data. Only some give you a working local number, and that is the line that should decide your choice.

Here is the reassuring part: for a normal visit, you do not need a Thai number. Grab — rides and food — runs perfectly well on your existing foreign number, maps and messaging need only data, and you can pay for most things by card or cash. So if you are here to sightsee, eat and get around, data is all you are buying, and the cheapest, simplest source of data is what you want.

A Thai number starts to matter when you go past being a tourist: opening a Thai bank account, using PromptPay, or signing up for local delivery and booking apps that send a one-time code to a Thai mobile — Thai banks in particular often will not send those codes to a foreign or virtual number. Most data-only travel eSIMs do not give you a usable Thai number, so if any of that is on your list, that single fact points you at a physical SIM.

The four options, side by side

Travel eSIM: the default for most visitors

If your phone supports eSIM — most recent iPhones and flagship Android handsets do, older and budget models often do not — this is the option that saves you the most hassle. You buy a Thailand plan from an app such as Airalo, Saily or Holafly before you fly, install it by scanning a QR code, and it activates the moment you land. There is no arrivals-hall counter, no passport scan, and no fiddling with a tiny plastic tray. A fixed data plan for a one- or two-week trip commonly comes to somewhere around US$5–13, with unlimited-data plans costing more.

The trade-off is what we said above: these travel eSIMs are data only. They roam on top of the Thai networks rather than being a network of their own, so coverage is fine, but you get no Thai phone number to receive local text codes. For a sightseeing trip that is exactly what you want and nothing you will miss. For anything that needs a local number, it is the wrong tool.

Physical tourist SIM: buy one when you need the number

A physical AIS or True tourist SIM gives you both data and a real Thai number, which is the whole reason to choose it over an eSIM. Tourist plans are sold by trip length — roughly a few hundred baht for a week up to around a thousand baht for a month — and usually bundle a generous data allowance with some call credit. Thailand requires SIMs to be registered against a passport, which is why you buy these over a counter where staff scan your document and activate the card for you.

Where you buy changes the price more than most people expect. The counters at Suvarnabhumi airport are open around the clock and genuinely convenient, but they charge a premium — reputable guides put the airport markup at roughly 20 to 30 percent over an official city shop, and some kiosks a good deal more. An official AIS or True shop in town is the best combination of price and help; 7-Eleven sells SIMs cheaply but with less choice and less English. Whatever you do, buy from an official operator counter rather than an unbranded kiosk, because the reported scam is a stall that quietly activates a smaller package than the one on the poster.

Staying a month or more? Skip the tourist product

Tourist SIMs are built for convenience over a short window, not value over a long one. If you are in Bangkok for a month or more — a long stay, a visa run turned into a season, remote work — a standard local prepaid plan from AIS or True works out cheaper per gigabyte and gives you a persistent Thai number, which is exactly what you will want once you start dealing with landlords, banks and local apps. You set these up in an operator shop rather than buying them off a tourist rack; bring your passport for registration.

Pocket wifi: the answer that stopped making sense

Pocket wifi — a little rental hotspot you collect and return — was genuinely useful in the years before cheap eSIMs, and travel-rental firms still advertise it hard. For a solo traveller in 2026 it is usually the worst of the three: you pay by the day, you carry and charge an extra gadget, and you have to return it on time or face a penalty, all to do a job your phone can already do by turning on its hotspot. It still earns its keep in a few honest cases: a group that wants to share one connection and split the cost, someone who needs several devices online at once, or a traveller who wants to keep their home SIM and number active without swapping it out. Outside those, an eSIM or a tourist SIM with hotspot enabled does the same thing for less.

A word on the networks and coverage

Thailand’s mobile market consolidated in 2023, when dtac merged with TrueMove H into True Corporation, so the practical choice today is between AIS and True (the dtac brand still appears on some products but sits inside True). Both run 5G across Bangkok and every touristy city, with coverage dropping to 4G only in rural corners and on smaller islands. For anything you will do in the capital — maps, Grab, video calls, uploading photos — either network is more than fast enough, and the choice between them matters far less than choosing the right type of connection in the first place.

Quick answers

Do I need a Thai SIM to use Grab in Bangkok?

No. Grab rides and food work on your foreign number with a card or cash. A data-only eSIM is enough. You only need a Thai number for services that text a code to a Thai mobile, such as a Thai bank account or PromptPay.

eSIM or physical SIM for Thailand?

Travel eSIM for most short trips on a recent phone — no counter, no passport scan. Physical SIM if your phone has no eSIM, or if you need a Thai phone number, which data-only eSIMs do not give you.

Is the airport the cheapest place to buy a SIM?

No, but it is the most convenient and it is open 24 hours. Expect to pay roughly 20 to 30 percent more than an official AIS or True shop in the city. Buy only at official counters, not unbranded kiosks.

Is “unlimited” data really unlimited?

Unlimited volume, not unlimited speed. You get a daily full-speed allowance, then a slower connection. Fine for maps and social; buy a big high-speed cap if you stream or tether a lot.

Is pocket wifi still worth it in 2026?

Rarely, for a solo traveller. It only wins for a group sharing one device or to keep your home SIM active. Otherwise an eSIM or a SIM with hotspot is cheaper and lighter.