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10-Steps to Buying & Using a Thai Sim Card & Mobile Data Plan

You’ve just touched down in sunny Thailand, ready for adventures from spotting elephants and lounging on stunning beaches, to late-night parties and making new friends.

You reach for your phone to let everyone back home know you’ve arrived… and maybe snap a selfie for social media.

But wait! No service, and airport Wi-Fi is slow. What now?

Don’t worry. This step-by-step guide will show you how to get reliable, affordable cell service in the Land of Smiles, so you can stay connected from the moment you land.

thailand sim card mobile data

Krista Stelzner, assigned to the U.S. 7th Fleet flagship USS Blue Ridge, snaps a selfie with a Thai girl during a community service event at The Child Development & Protection Center in Huay Yai, Thailand.

Step 1. Unlocking Your Phone

Using your home mobile plan overseas can be inconvenient, and often surprisingly expensive.

Before you travel, make sure your phone is unlocked by your home network. An unlocked phone can accept a Thai SIM or eSIM, which is cheaper, faster, and far more practical than relying on roaming. Many providers unlock phones for free once your contract ends, but it’s best to check before you fly.

It’s also worth knowing what kind of SIM your phone supports. Most modern phones now use nano SIMs, and many newer iPhones and Android devices also support eSIM or dual SIM, allowing you to keep your home number active while using a Thai SIM for data.

If you’re unsure, a quick Google of your phone model will tell you exactly what it supports, and if all else fails, staff at mobile shops in Thailand can usually check and set everything up for you in minutes.

Step 2: Deciding on Roaming vs. Thai SIM Card

Some travellers want to keep their home number active, which usually means turning on international roaming.

You can do this, but it’s rarely the best option. Roaming charges for data are often high, limits are tight, and it’s very easy to rack up an unexpected bill — even if your provider claims to have “travel-friendly” packages.

A far cheaper and more reliable option is to use a Thai SIM or eSIM for data and local calls, and rely on apps like WhatsApp, Line, or FaceTime to stay in touch.

If your phone supports dual SIM or eSIM, you get the best of both worlds:

  • Keep your home number active for SMS verification or bank messages
  • Use a Thai SIM for fast, affordable data

For most visitors and expats, roaming simply isn’t necessary. Buying a Thai SIM at the airport or from a local provider shop is quick, inexpensive, and usually takes just a few minutes.

Step 3: Getting a Sim at the Airport Vs a Provider Store

If you’re staying in Thailand for a week or less, buying a SIM at the airport can be convenient. Airport plans are designed for tourists and usually include data, local calls, and texting for short stays. You’ll pay a little more for convenience, but it’s quick and hassle-free.

For longer stays, it’s usually better to visit a provider store or booth in a shopping mall. There you’ll find a wider range of plans, better value for money, and more flexibility if you plan to stay weeks or months.

Another popular option is using a data-only eSIM. If you want to keep your home number active for calls or SMS — especially for banking codes — an eSIM for data works very well. Services like Saily let you activate mobile data before you even land, with no physical SIM to swap and no shop visit required.

In most cases, buying a physical SIM in Thailand requires a passport, as SIM cards are registered to your name. This is standard practice. While smaller shops may not always ask, you should assume registration is required and carry your passport with you.

Step 4. Choosing Your Provider & Your Plan

Thailand has three main mobile providers: AIS, TrueMove H, and DTAC. All offer prepaid, pay-as-you-go plans suitable for tourists, retirees, and long-term expats.

All three providers now offer fast 4G and 5G coverage across most of the country, including cities, towns, and popular tourist areas. For everyday use — messaging, maps, streaming, and hotspotting — any of them will work well.

Most plans come in daily, weekly, or monthly formats, with options ranging from capped data allowances to “unlimited” data at a capped speed.

Quick provider overview:

1. AIS

Often considered the most reliable network nationwide, especially outside major cities. Strong coverage, good speeds, and an easy-to-use app for managing plans and top-ups.

2. TrueMove H

Competitive pricing and very good coverage in urban areas. Known for offering plenty of Wi-Fi hotspots around Thailand, which can be useful if you’re trying to save mobile data.

3. DTAC

Generally user-friendly for foreigners, with clear English support and simple prepaid options. Coverage is solid in cities and tourist areas.

In recent years, all providers have made managing your plan much easier through their mobile apps, where you can:

  • Check data usage
  • Buy or change plans
  • Top up credit
  • Contact customer support

Rather than chasing a specific deal, it’s best to choose a provider based on coverage where you’ll be staying, and then pick a plan that matches how much data you realistically use.

Step 5: Topping Up with Credit

Adding credit to your phone — known locally as topping up — is quick and easy in Thailand.

You can top up at:

  • 7-Eleven stores (almost everywhere)
  • Mobile provider shops or mall booths
  • Street kiosks and top-up machines
  • Online via your provider’s mobile app

Once you’ve added credit, you can use it to activate data, call, or text packages. The cost of your chosen plan is simply deducted from your available balance.

These days, the easiest way to remember is: use the app. All major providers offer English-language apps where you can do all the things mentioned in the previous section.

You can still activate plans via dial-in codes or by calling customer service, but most people find the app far simpler. Providers also regularly offer promotions or bonus data, especially for app users, which is handy if you’re watching your budget.

Step 6: Tethering from Phone to Laptop

Spotty Wi-Fi is a common frustration for travellers. If you want to use a laptop or tablet while out and about — or if everyone in your hotel is hogging the Wi-Fi — your phone can act as a personal hotspot.

A few things to keep in mind:

  • Hotspotting uses a lot of data, so a large or unlimited data plan is recommended.
  • Check your provider’s app or plan details to avoid unexpected throttling once you reach your limit.

How to set up a hotspot:

iPhone / iPad

  • Go to Settings → Personal Hotspot
  • Turn Allow Others to Join on
  • Choose a Wi-Fi password if prompted
  • Connect your computer, tablet, or other device via Wi-Fi, USB, or Bluetooth

Android

  • Go to Settings → Network & Internet → Hotspot & Tethering
  • Turn on Wi-Fi Hotspot
  • Set a password if prompted
  • Connect your other device

Hotspotting is a convenient way to stay connected, especially if you have multiple devices, but always keep an eye on data usage to avoid throttled speeds or extra charges.

Step 7: Guarding Your Data

Most Thai prepaid plans give you a set amount of high-speed data, and once you hit that limit, your speed is throttled, often to levels slow enough that browsing or streaming becomes frustrating.

A few simple strategies can help you make your data last:

  1. Use Wi-Fi whenever possible: Most cafes, restaurants, shopping malls, and even some public areas offer free Wi-Fi. Thai providers also have mobile Wi-Fi hotspots scattered around cities.
  2. Save heavy activities for Wi-Fi: Video streaming, large downloads, and cloud backups can quickly eat your data allowance.
  3. Adjust app settings: On both iPhone and Android, you can:
  4. Turn off cellular data for apps you don’t need to use on the go
  5. Enable “low data mode” or “power saver” to prevent apps from refreshing in the background
  6. Consider a VPN: Not only does it help protect sensitive information on public networks, it can also reduce background data tracking in some apps.

Being mindful of your usage ensures you get the most out of your plan without surprises, especially if you only top up once or twice during your stay.

Step 8: Avoiding Over Charging

One of the best things about prepaid or pay-as-you-go plans in Thailand is that you won’t get a surprise bill — once your credit or data runs out, services simply stop until you top up.

To stay on top of usage:

  1. Enable alerts: Most providers can send notifications in English when your data, call minutes, or texts are running low.
  2. Use the provider’s app: You can quickly check your remaining balance, top up, and see when your plan expires. Apps often give real-time usage updates and can even remind you to renew or extend your plan.
  3. Note expiry times: Many daily, weekly, or monthly plans have fixed validity periods. Knowing exactly when your plan ends prevents frustrating downtime, especially if you rely on your phone for navigation or contacting friends.

Step 9: Staying Active

How long your SIM lasts depends on the type you have. Most prepaid tourist SIMs are valid for about 30 days after topping up. For longer stays, topping up regularly keeps your SIM active and your number usable.

Checking your expiry:

Via app: All major providers (AIS, TrueMove H, DTAC) let you see your remaining validity and data in their mobile app — the easiest and fastest method.

Via USSD codes: If you prefer, you can still check manually:

  • AIS – *121#
  • DTAC – *101*9#
  • TrueMove H – #123#

Using the app is generally simpler, and it also lets you top up, buy new packages, and see your remaining data in real time.

Tip: Even if you rarely use your SIM, topping up at least once every 30 days helps keep your number active.

Extend Your SIM’s validity

To extend your validity:

AIS:

  • Add 10 Baht credit for 30 Days Validity
  • Alternative method: Dial *500*9#  Add 30 days validity for 30 THB via Mao Mao package

DTAC:

Extend your validity for up to 365 days, at a cost of 2 Baht per month.

  • Press : *113*30*9# for 30 days extension.  Cost 2 Baht
  • Press : *113*60*9# for 60 days extension.  Cost 4 Baht
  • Press : *113*90*9# for 90 days extension.  Cost 6 Baht
  • Press : *113*180*9# for 180 days extension.   Cost 12 Baht
  • Conditions: Must activate SIM for at least 90 days or have usage of 200 THB.

TrueMove H:

Extend your validity for up to 365 days at a cost of 2 Baht per month

  • Press : * 934 * 30 # for 30 days extension.  Cost 2 Baht
  • Press : * 934 * 90 # for 90 days extension.  Cost 6 Baht
  • Press : * 934 * 180 # for 180 days extension.   Cost 12 Baht

Step 10: Contacting Customer Service

If you have questions about your SIM, plan, or international roaming, all major Thai providers make it easy to reach them. Most support is now app- or LINE-based, which is faster and more convenient than calling.

Customer support options:

DTAC

  • Call from your phone: 1678
  • LINE: @dtac
  • Email: feedback@dtac.co.th

AIS / One-2-Call

  • Call from your phone: 1175
  • LINE Messenger: @12Call_Fan
  • Email: callcenter@ais.co.th

TrueMove H

  • Call from your phone: 1331
  • LINE: @truemoveh

Tip: For most quick queries such as plan details, topping up, or checking coverage the provider’s app or LINE support is usually the fastest option. Calls may take longer if you don’t understand the Thai menu options, although most providers offer an English option.

Tips to Start Planning Your Trip Now

Don’t Forget Travel Insurance:

Travel insurance protects you against illness, injury, theft, and cancellations. I never travel without it. I’ve been using SafetyWing for years. You should too.

Need an e-SIM?

My personal e-SIM recommendation is Saily. Read about it here.

Improve Your Thai Skills:

Learning Thai makes life much easier here, and more fun. I use Thaipod101. Click here for a free account. It is really easy to use.



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Comments Sort by : newest | oldest

  1. Gary says

    This is probably a silly question i have a Iphone6 i am looking for a pre paid package that still give me accees to my messanger and Line Account as they are my main sourse of comms any help will be greatful
    Reply

  2. James E says

    I uncovered (by accident, of course) something that's new to me but very helpful if you're a regular visitor to Thailand but don't actually live there. It's the DTAC "Call" app (a very catchy name, huh?). Basically, it's a Voice/SMS/MMS over IP service that is linked to your Thai phone number. Need a One Time Password for a banking or phone app login it shows up on your mobile. Anywhere in the world. Don't want to force friends or family to use up their Thai data plans on Skype or Line, they can just dial or text your Thai number and your phone goes *bing*. Anywhere in the world. The app is free but (and here's the biggest selling point) using it only costs as much as it would on your SIM/Plan in Thailand. No more international charges for phone calls to or from Thailand. But, (it's Thailand, there's always a "but") setup is not the easiest. First, dtac has eliminated the email support option and want you to go through a Social account for support, I used Facebook. This means, in my case, I had to turn on international roaming on my SIM to get the OTP to register myself to the app. DTAC, to their credit, had me jump through some additional information hoops to prove it was really me and not some bot seeking to destabilze a democracy or whatnot. Second, with international roaming enabled, you start the app and request your OTP to authorize the app to the system; which takes a couple of minutes. From this point on you do not need your SIM anymore. You can install the app on any phone (haven't tried it on a tablet so don't know if that works) and it will work just fine. I haven't checked but I imagine the other mobile providers have or will soon have something similar. So far the app, unlike using the SIM, has not burned any data communicating back to the mothership in Thailand so that's a help, too.
    Reply

    • TheThailandLife says

      Interesting. I wonder if this keeps your SIM active too? Many infrequent visitors find that by the time they return their SIM has expired because they haven't used it and they have to get a new number. If you activate and use this service would it signal that the number is in use?There's always WIFI, but this is handy if you're out and about and not on a WIFI connection.
      Reply

      • James E says

        I'm thinking not. The SIM needs to stay active to have a plan and funds attached to it. (Although, possibly, the plan may be attached to the number instead of the SIM. Dunno.) But what it does do is give you a way to set up the DTAC app or use the website to add funds to your SIM and buy extensions to keep the SIM active wherever you happen to be when not in Thailand without incurring the onerous data roaming charges. One of the neat things about the Call app is that it will work over any data connection - 3G, LTE, or WiFi. That means I can use the app over my US Unlimited LTE plan and incur no data use at all.
        Reply

  3. Andy says

    Hi,
    Thank you for sharing your knowledge! This is very helpful.
    I will be in Thailand for 44 days - just over 7 weeks.
    I will be travelling the Islands, Bangkok and Chiang Mai. I will need to be able to text and facetime internationally as well as use various apps including Whatsap, Snapchat, Instagram, Facebook, Grab, Maps.Com and Life 360. What would be your recommendation for sim card and data package?
    Would you know if there is a sim card I can purchase that would cover the entire duration of my travel? Do you know if I would have to purchase a separate data package or is the data included with the sim card purchase?
    Thanking you in advance for your advice.
    Reply

    • James E says

      First, pretty much all of the carriers will give you country-wide voice/text/data coverage so find one (dtac, True, or AIS) whose website you like the best. The reason for this is that each handles its prepaid plans differently - even though you're getting the same product - so you'll want one whose plans make sense to you. Not that that will be obvious when you first start. I use dtac so I'll talk from that. Prepaid in Thailand is different in that you don't buy a plan that covers all your needs you get a base plan - voice, text, and data - and then add options to that plan to make the data affordable and fast. UNDER NO CIRCUMSTANCE PAY THE BASE RATE FOR DATA. Period. You choose your data package based on anticipated use and speed requirements. You'll have to dig a bit to find the optimum plan as the stop at the top level tends to be pricey and slow compared to what you can find. Make sure you don't get an auto-renew plan. Plus the plans change all the time so what I used last November might not be available now. It's like a game. SMS is pretty affordable but I have problems receiving text/media from US numbers to my dtac number. Just get a regular SIM, the SIMs cost the same as a "tourist" SIM (49THB last time I looked) but you won't get stuck with a number that expires midway through your trip and the plans will be a bit cheaper. I usually spend 300-500 baht a week for all services. Since you're going to be data heavy look into a VPN if you don't already have one. You. Really. Want. A. VPN.
      Reply

  4. Mj Silva says

    I am actually connected to AIS Prepaid BAO-BAO PLAN (sorry i don't know the full name of the plan) something, it's a 1 mbps unlimited internet for 6 MONTHS for only 600 BAHT, take note, 6 MONTHS, if you just want to have spontaneous mobile data/internet connection and you're using applications for messaging/calling purposes, you can subscribe to this plan.
    its only for 600 BAHT, so basically 100 baht a month for 1MBPS internet, usually its not just 1 mbps its up to 4 mbps, I can even make HD calls to the Philippines using LINE.
    Reply

  5. Fran D says

    Hi everyone, Im new on here so here goes, planning on going to Thailand via BKK airport in February some time in Bangkok, some in Kaanchanaburi, thereafter who knows! but want to get a data sim for my mobile wifi dongle so 2 of us can tether to it as needed. Last year when we went we were advised to visit AIS at BKK airport which we did, bought a Data sim but it wouldnt connect to internet so they refunded me, no english speaking staff available to help so left it and visited anothe AIS store in Terminal 21 on Sukhumvit but again staff unable to assist with connecting it to internet. Is there something I need to be doing? dongle is unlocked, and works in othe countries, do I need to change APN details myself or will store do it? do I need to activate the sim myself or will staff do it in store. I ask because despite it never connecting to internet I received numerous messages in Thai/English on to the dongle that I only discovered weeks later when I got back to Blighty and reinserted by UK sim. Any wise words of wisdom appreciated
    Reply

    • James E says

      AIS advertises that they support the service so you should be able to make it work. Your APN may be the issue or it may be something on the network side. I'd suggest going to a store in a - I hate to say this - more upscale place than T-21, like Em or Paragon. I've not used AIS but dtac has a dedicated queue for English speakers in both so would assume AIS is the same.
      Reply

  6. Rudy spiessens says

    would you say your comments of 2017 are still valid? I went to all 3 stores (Nov 2018) and all of them only offer quite large data packages, like 2G minimum at around THB220. Coming from South Africa, those data bundles are cheap but I only need like 1Mb only per month. So if I can still purchase a SIM card and then extend it's validity and keep it topped up, that would sort me out. The sales people don't seem to aware of these options.
    Reply

      • Rudy spiessens says

        Thanks. Next problem. I purchased a True Move sim card. Whit most USSD codes, except 2 or so, one get's a Thai response. When dialing 9304 to change the language, one gets a Thai voice message !!! Unbelievable how some software people think.
        I'm hoping for a solution
        Reply

    • James E says

      Rudy,
      1 MB or 1GB? I wouldn't think 1MB would even cover email and app background data.

      If 1 MB just pay-as-you-go. I think that would work out to less than a package.

      Otherwise it depends on how long you're going to be in Thailand. I don't use much data so I get the 400MB/wk Max-Speed plan from dtac. It's like 60THB+/-. I use the old * code to access it. They also have a monthly plan that's about what you described price-wise but I think is a 4GB plan.

      The reps in the store really don't have an idea as to the full offerings. I've always found prowling through the websites and apps to be the best way to find the bargains.
      Reply

  7. James E says

    I just got to Bangkok yesterday and found that a couple of things have changed with dtac's pre-paid services.

    First - The online offerings are pared way down. In the past you could dig around the website and find deals that were not in their easy-to-find pages. No more. The "*" codes have vanished from site and the website offers are mostly the high dollar auto-renew plans.

    Second - dtac's app (I'm on Android but imagine iOS is similar) is where all the action is now. It shows (easily) 20 times more prepaid options than the website which range in price from less than 10 THB on up with validity times from one day to a month. This is where you'll find all the 7-day plans useful for shhorter stay visitors.

    Third - the plans have gotten better and the prices have come down. The plan I used to get which was 1GB of 100Mbps data (through a "*" code) and cost 79THB a week has been "replaced" by a 2GB 100Mbps plan that costs 49THB a week. While I'm sure my old "*" code would work, why would I use it?

    The app also provides better account management than the web without all the one-time password nonsense.
    Reply

  8. Luc says

    Hello, just moved to Bangkok with family. I have from employer a Truemove H subscription. Question : I need 4 SIM cards , for next 3 years mini, one for wife and 3 teenagers, all needing datas . Ideally like in France : one manager of the datas that can be the wife of course. Which provider/subscription do you advice ?
    Thanks for your answer.
    Reply

  10. Josh Mannen says

    My old fashion mom is coming to visit me in mid-July. She has a very old fashion CDMA flip phone, that will not work here. I am planning to get her a new cheap GSM phone, on the DTAC network (because that is what I am on) I want to have it ALL set up and tested and then just send it to her, so when she steps off the plain, all she has to do is turn on the power and dial or text. My thought is that I put her on the 49 baht / Go Plearn SIM with Free internet (to prevent data leakage) and extend her validity for 90 days with an extension at the cost 6 Baht. I didn’t understand in “Conditions” you say: “Must activate SIM for at least 90 days or have usage of 200 THB.” Does that mean she has to have been active for 90 days or have used 200 baht to do the extension? If that is the case, could I still set up and test the phone, with Go Plearn and then go online the day before she comes and do a “refill to” her number at the DTAC website. Thanks in advance. JOSH
    Reply

    • James E says

      Hey Josh,

      Short answer is Yes: You have to have the SIM active for 90 days or have burned through 200 baht (which, as you know, is very easy). I think if you add a few hundred baht credit though you'll automatically get the 90 days validity. I'm not sure what the minimum is (maybe 300 Baht) so check with dtac on that. The Go Plearn SIM doesn't come with any credit so you'll have to add some anyway.

      Second thing is all dtac prepaid SIMs are the same, 49 Baht. What you get with the different SIMs is some default apps and default calling rates. Those are changeable if you want. I've found that the plan (SIM) you get should be driven by how you're planning on using the phone. I'm assuming your mom will be calling/texting rather than surfing the internet. Check out the other SIMs as well in terms of the call rate (MMS/SMS rates are the same regardless of SIM). For example, I've got a Super 4G SIM that I put a data package on so I don't have to pay the data rate. The call rate is broken down into seconds so a hypothetical 1 minute, 1 second call costs 1.005 Baht. That same call on the Go Plearn SIM is 1.38 because you pay by the minute. However calls shorter than a minute would be cheaper. Also look at the Gift SIM as it includes some free data for topping up which would give her some internet use and more speed than the Go Plearn along with calls being billed to the second.

      So, it doesn't matter where you start, Go Plearn or another SIM, you can always switch the main plan or add-on plans to get the features and cost you want.
      Reply

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