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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. frank peeters says

    i use a small mobile wifi router from TP-link. It handles multiple connections, my wife's and daughter's phone also make use of it, although with multiple users it does drain the battery faster, for us three it usually lasts more than a half day on a full charge. I let the provider at the airport install the sim card and set it up for which service i am happy to pay a bit more
    Reply

  2. Chris says

    Hi James, I need to use a Thai banking app which will require a Thai SIM or E-Sim card. Is it possible to buy a pre-paid card and top up monthly? The Sim is only used for SMS for banking purpose only . Would it be cheaper than buying a Post-paid plan? Can the Sim or E-Sim be activated on the same day of purchase?
    Reply

    • JamesE says

      In general, yes, your cheapest option is pre-paid for the low-use scenario you describe. One thing to be aware of, though, is that pre-paid balances expire. To get around that (I'm only in Thailand part of the year) I use dtac which has the inappropriately-named service called JaiDee Day Giveaway. For ฿3 you extend your balance expiration day by 30 days without needing to do a monthly top-up. You can extend by up to 180 days/transaction, so two transactions gives you a year, in essence. If you buy your SIM/eSIM from a local vendor they'll activate it on the spot. If you buy before arrival you just enable the line in Settings and it activates itself.
      Reply

        • JamesE says

          The only issue I can see would be that the initial SIM activation is done in Thailand. So, you can buy and install the eSIM on your phone anywhere but it won't work until it shows up on the Thai network. There's a lot more control on this sort of thing in Thailand because Thai SIMs are frequently used in call center scam operations run jusy over the borders of Laos, Cambodia, and Myanmar.

          Otherwise, it's pretty straightforward, buy the SIM, top up with a few hundred Baht, and you're good to go. The JaiDee Day Giveaway is only to extend your balance's (and SIM) validity so don't wait until expiration to buy more months. The ฿299 plan eSIM you mention is only good for 8 days and comes with just ฿15 in usable balance (SMS cost ฿3/each). So top it up as soon as you install it. As long as you keep an active balance the SIM itself will remain valid.
          Reply

  3. Joe says

    Hi, as a tourist who will be in the country for 6 weeks I will need to purchase what looks like its going to be a 30 day plan and then another 2 week plan. The costs for "traveler" plans are much more expensive than those for local thais. Am I stuck with buying a traveler plan or are foreigners able to buy plans that a thai person is able to at reasonable prices? I've read that's possible with physical SIM cards but my phone ONLY has the option for E-SIMs.
    Thanks.
    Reply

    • JamesE says

      You can buy eSIMs online for dtac and AIS (not sure about True but I'm guessing so). There's really no difference between the tourist and "regular" SIMs functionally so you can get a cheap eSIM, add some balance and then buy the plan(s) that fit your needs. I use dtac so I'm most familiar with them. Check out https://www.dtac.co.th/en/new-number/esim for online purchase (note: the Tourist eSIMs may be your cheapest option for the short time period you're talking about. Your other (and probably cheaper) option is to go to a physical outlet and get one at the source. But that will take some time out of your trip. Regardless of which you choose you will, as you suggest, need to get two plans - at least for data.
      Reply

      • JamesE says

        eSIMs can also be purchased online and activated immediately on arrival. They send you QR code which you scan to load into your phone. When the wheels hit the ground just enable the eSIM on the iPhone 15's second line and you're good to go.
        Reply

    • Rick says

      The iPhone supports multiple eSims. So you can typically get another eSim wherever you are traveling and have it added to your phone. Make sure that you correctly configure your phone to use the traveling eSim for calls and data, otherwise the phone will default to the 'native' Sim with which you bought your phone..
      Reply

    • JamesE says

      You'd have to check with the individual carriers as plans change constantly. And are you talking pre-paid or post-paid? For pre-paid, unlimited plans are often low-speed - 10-20Mbps - or throttled so you get high-speed up to a certain volume and then the speed falls back. You can buy an add-on (everything seems to require an add-on) that can boost your speed. But, again, there is always a catch like volume limits. So, while you may have unlimited data, you'll be buying one or two extra packages a month to keep it at high speed. I use dtac and just buy one of the 100Mbps limited data packages (I think they're 4, 12, and 24GB levels) as I don't need unlimited data. Also look at AIS's 5G plans. I've heard they're pretty good with the downside that most of the time you'll be on 4G. If you want post-paid your best bet is to go to a carrier store and explain - in excruciating detail - what you need and whether they have a plan for that.
      Reply

  6. Rick says

    This is slightly off topic but I am moving to Thailand permanently and currently have an iPhone and Watch. Any advice on whether I can just move my phone & watch onto a Thai plan after I cancel my US plan? Or would getting new devices be the way to go?
    Reply

    • JamesE says

      Depends on whether your devices are still tied to your carrier, AKA: Locked, or not. If locked, you'll have to get your US carrier to unlock them first. After that, no problem. If you have recent editions of your tech it's easy. iPhone X (XR?) - 13 are all dual-SIM phones with one physical SIM and one eSIM. iPhone 14 is dual-eSIM. So, you just stroll into a Thai carrier store, pick a SIM, pick a plan, and you're good to go. If your Watch is cellular, it'll be the same deal.

      Thai cellular plans are structured differently than US plans. There are different "kinds" of SIMs that have different base pricing structures and you add calling plans or data plans on top of that. And you can add data speed on top of that. There's also a big difference between pre-paid plans and post-paid. In general, you'll get a better pricing structure on a pre-paid plan (i.e. cheaper but more management) unless you just don't want to think about it and get post-paid.

      Have a look at the three carriers' websites: AIS, True, and dtac. AIS tends to get the best reviews but all have excellent coverage and robust networks. I use dtac because it supports use outside of Thailand essentially for free (well, same cost as in Thailand) with no roaming plan required.

      Lastly, don't get rid of your US number. Migrate it to a VOIP service (I use voip.ms). That, combined with a VPN, will make managing any US communication needs - like 2-factor authentication - much easier.
      Reply

    • JamesE says

      Do you already have the SIM? The One-Day Deals are typically stand alone and not part of a package. Which One-Day Deal are you asking about? The carriers all offer several options for data/voice or either that can be paid day-to-day. Also, it depends on whether your asking as a longer-term visitor (> 1 month) or a shorter-term visitor (< 3 weeks). In general you will be better served by getting the longest term plan you can for the length of your stay with the goal of not leaving any money in your account when you leave. So, say you're here for 3 weeks, compare the cost of a two-week PLUS a one-week plan to the cost of a one-month plan, and so forth. That compared to the cost of 30 days of a daily plan will be cheaper. But, going back to the top, it all depends on which plan you're asking about.
      Reply

      • Simon says

        Hi James,

        I need an internet service that provides me with the same level of high speed (25 mbps+) and data (unlimited) that I have in the UK (from BT/EE), albeit through broadband over here, for which I pay around £70 per month (so, around THB3,000 equivalent).
        So, is this combination of speed and data available on pay-as-you-go SIM card only plans over there - and if so would it be more or less than THB3,000 per month do you think)?
        Or would I be better advised to get one of those mini-broadband hubs from a provider store do you think and, if so, is it straightforward to do so?
        It is my intention to stay in Thailand, as from June?
        Thanks in advance for your help and forgive any techncial ignorance on my part, as previously all I have done is just take out broadband plans wherever I have lived with everything included.
        Reply

        • JamesE says

          Hi Simon,
          Typically, the speeds on unlimited plans are slower than on metered plans but vary between the carriers. I'm on a dtac pre-paid plan and their "high speed" plans are typically in the 20-25Mbps range. But, (there's always a but in Thailand) the carriers also offer true high-speed data in either base plans or add-ons. I use dtac's Internet Max Speed plans which get me 100Mbps (actual is more like 50 as I go through a US server on my VPN). They're available in 6, 18, and 36GB for 30 day bundles for the absurd price of ฿199, 299, or 499 respectively.

          I've heard good things about AIS's offerings as well but don't have direct experience with them. Same with True (now merged with dtac) although the True commenters don't seem to have the partisan fervor of AIS's. dtac serves my needs nicely as they have a VOIP app (dtac Call) that works globally for voice and SMS at the same price as in Thailand.
          Reply

          • Simon says

            Hi again, James; quick question on your VPN (which I will also be using, of course), but do you also have the VPN on your phone - for banking apps I'm thinking of?
            I suppose it would make sense, but when I did it in the UK (admittedly using a less fast than say NordVPN, in ym case Avast VPN) my phone was going at a snail's pace.
            Also, by the way, as I'm on the subject, is it NordVPN and Vyper as well that you would recommend (I know Peter uses them).
            Ideally, aside from security, I want to be able to stream as many of my usual TV streaming sites as possible (Netflix, BBCI Player, ITVX - it's a regular site, by the way, ahem, despite it's odd title, and maybe Amazon Prime).
            Reply

            • JamesE says

              I am clinically Data Paranoid (I think that's the term from the DSM...) so, yes, I run a VPN on my phone (Surfshark, it handles network switching better than Vypr (which I run on my PC)). There's a speed penalty with any VPN so a lot will depend on the speed of your cellular network (I use 100Mbps on dtac) as well as your server choice. For me (needing to get US content) it's much faster if I go to a West Coast server than central or East Coast.I haven't tried Nord as their rates are too pricey for my budget but use Vypr on my laptop and Surfshark on my mobile devices. (Both of which together cost me less than a Nord subscription.) I used Avast in the past but found their performance a bit sluggish plus they didn't handle sites which drop known VPN connections quite as well as the others.
              Reply

              • Simon says

                I share your particular paranoia, James - and, as the saying goes, 'just because you're paranoid doesn't mean someone isn't out to get you'.
                Both of your recommendations are extremely well noted on my part, as has been all of your terrific advice on this.
                Thank you very much, James, and have a great remainder of your evening.
                Reply

              • Simon says

                Good afternoon, James - a quick supplemental question: is there any particular reasons (speed, security, whatever) why you don't use Surfshark on bith your laptop and phone?
                Thanks again in advance for your answer on this and best regards.
                Reply

                • JamesE says

                  Hello, Simon. I have found that Surfshark is good enough but that Vypr's performance is better. Where Vypr really shines is in keeping their servers up and running. Surfshark's Thai server, in several instances, has vanished off their network and has taken weeks to get back online. This is not too big a deal as I'm mostly using a US server. However, if I really need to use that Thai server, it's fatal.

                  BUT Vypr can have times where their performance goes downhill on one server but is fine on a second. This requires a manual switch of servers which is no big deal on my laptop but a pain on my phone (largely because it's in my pocket and I'm unaware that it's running slow...).

                  So, in addition to having a backup for times when I need it (like right now with Surfshark on my iPad), that's why I have two VPN subscriptions.
                  Reply

                  • Simon says

                    Hi, James - so a quick update for people who might have thought about using NordVPN.
                    I bought it earlier today, installed it, and tested it by trying to watch Netflix (I am a subscriber) using several different servers, including one in the UK (which is where I am sitting).
                    Not only did it not manage to stream it but also Google picked up on odd activity and I kept having to tell it where traffic lights were.
                    I then tried to do the same with BBCiPlayer (paid subscriber through TV licence, no chance), ITVX (paid subscriber, nope), Prime (paid subscriber, not a hope), AllFour (no).
                    In short, not a single site I usually visit allowed me to proceed. And no streaming site worked - just buffering.
                    So, I have now asked for a refund and uninstalled it all.
                    I shall try Vypr - as you suggested, and also Peter - and see what happens there.
                    Reply

                    • TheThailandLife says

                      Hey Simon, that's strange. Nord works well for me. Their Thai server has actually been more reliable for me than Vypr over the last few months. Did you close Chrome before starting your VPN? Also worth using the incognito browser option in Chrome.

                    • Simon says

                      This is in answer to Peter, but there is no 'Reply' bit in your comment.
                      I use Edge as a browser and sometimes Firefox, so maybe that had some impact.
                      However, when I just talked to Nord (in addition to sending them the required email for my refund) they said they have had some problems with Google across many of their servers in the past few weeks.
                      I tried ExpressVPN a whiel back and that was useless as well.
                      Perhaps it is because I have AvastOne as my security software but I checked that out specifically with bothe sets of VPNs (Express and Nord) and they said it did not make a difference.
                      My broadband here is around 50 mbps (EE/BT broadband) so I don't think it's that either.

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