AIS, DTAC, TrueMove in Japan: Using Your Thai SIM Abroad Seamlessly

You land at Narita, your phone buzzes with a flood of messages, and then you notice you never activated a data package. Thai travellers lose money this way every year, because standard roaming rates without a package can be extremely expensive. In 2026 the choice is wider than ever. You can keep your AIS, DTAC or TrueMove H number and add a roaming package, or you can add a Japanese eSIM, tourist SIM or Pocket WiFi. This guide covers both routes, with the steps, the costs and the mistakes to avoid. Prices are approximate 2026 figures and can change, so check each provider’s official site before you travel.

Before You Fly: Ground Rules for Thai SIM Roaming

Whichever operator you use, the same few habits keep your trip free of surprise charges.

• Always activate a roaming package. Do it before departure, or right after you arrive, through the operator’s app or a USSD code.
• Turn on “Data Roaming” in your phone settings. Without it, even an active package will not connect.
• Check your remaining allowance regularly in the operator’s app.
• Turn data roaming off if you have no active package.
• Make sure your passport is valid for travel. You will also need it if you buy a local SIM in Japan.

Roaming keeps your Thai number active. That matters if you receive bank OTP codes by SMS, which is a good reason to keep your Thai SIM in the phone even when you use a Japanese data eSIM.

AIS, DTAC and TrueMove H Roaming Packages: Step-by-Step Activation

All three operators offer an Asia-focused package and a wider global package. The figures below are approximate 2026 prices. Each operator also has an official roaming page (for example ais.th/roaming, dtac.co.th/gointer and truemoveh.truecorp.co.th/roaming), so check there for the latest details.

AIS (SIM2Fly and Roaming Packages)

AIS is known for its SIM2Fly service. You can buy it as a standalone SIM, or add roaming packages to an existing pre-paid or post-paid AIS number.

• Asia & Australia Package: about 1,800 JPY (429 THB) for 20 GB of high-speed data, valid for 10 days. After 20 GB, speed drops to 128 kbps.
• Global Package: about 2,600 JPY (599 THB) for 15 GB of high-speed data, valid for 15 days.

1. My AIS app: download it from Google Play or the Apple App Store and log in with your AIS number. Open the “International Roaming” or “Travel” section, pick the Japan package and confirm.



2. USSD code: dial *111*XXX#, where XXX is the package code. For example, *111*359# is used for an Asia package. Follow the prompts and wait for the SMS confirmation.
3. Call centre: call 1175 in Thailand, or +66 2271 9000 from abroad (charges may apply).

The cost is deducted from your pre-paid balance or added to your post-paid bill.

DTAC (Go Inter)

• Asia & Australia Package: about 1,800 JPY (429 THB) for 20 GB of high-speed data, valid for 12 days. After 20 GB, speed drops to 128 kbps.
• Global Package: about 2,600 JPY (599 THB) for 15 GB, valid for 15 days.

1. DTAC App: download it, log in, open the “International Roaming” section, then choose the Japan-compatible package and activate it.
2. USSD code: dial *118*XXX#, where XXX is the package code, and follow the prompts.
3. Call centre: call 1678 in Thailand, or +66 2202 8100 from abroad.

TrueMove H Roaming

• Asia Zone Package: about 1,800 JPY (429 THB) for 20 GB of high-speed data, valid for 12 days. After 20 GB, speed drops to 128 kbps.
• World Zone Package: about 2,600 JPY (599 THB) for 15 GB, valid for 15 days.

1. True iService app: download it, log in, find “International Roaming” or “Travel” and choose your package.
2. USSD code: dial *110*XXX#, where XXX is the package code.
3. Call centre: call 1242 in Thailand, or +66 9991242 from abroad.

Japanese eSIMs and Tourist SIMs: When Local Beats Roaming

Roaming is easy, but local products can give you more data for the money on longer trips. Several of them also let you keep your Thai SIM in the second slot, so your Thai number stays reachable. Many newer phone models are eSIM-only, which makes eSIM options even more useful.

aHashtag eSIM

aHashtag focuses on travel eSIMs. You buy online, receive a QR code by email and scan it in your phone settings. No pickup is needed. It uses major Japanese carriers (Docomo, au, SoftBank), depending on the plan. Its data-only plans cost approximately:

• 5 GB for 7 days: 1,500 JPY
• 10 GB for 15 days: 2,700 JPY
• 20 GB for 30 days: 4,500 JPY
• Unlimited data for 30 days (throttled after a daily high-speed cap): 6,000 JPY

Sakura Mobile

Sakura Mobile offers SIMs, eSIMs and pocket WiFi, with strong English support. You can order online and have it delivered to your accommodation in Japan or collect it at Narita (NRT), Haneda (HND) or Kansai (KIX). The eSIM QR code arrives by email for instant activation. Approximate prices:

• Physical SIM (data-only): 5 GB for 8 days at 2,800 JPY; 10 GB for 15 days at 4,500 JPY; 30 GB for 30 days at 6,500 JPY.
• eSIM (data-only): 5 GB for 8 days at 2,700 JPY; 10 GB for 15 days at 4,400 JPY; 30 GB for 30 days at 6,400 JPY.

IIJmio Japan Travel SIM

IIJmio is a Japanese MVNO (a virtual operator that rents network capacity) running on Docomo’s network, so coverage is wide. These are physical data-only SIMs, with approximate prices of:

• 3 GB for 30 days: 2,500 JPY
• 6 GB for 30 days: 3,500 JPY
• 10 GB for 30 days: 4,800 JPY

You can buy online from the official IIJmio site (iijmio.jp/prepaid/en) or from authorised resellers such as Bic Camera and Yodobashi Camera online. You can also collect at NRT, HND or KIX with your order confirmation and passport. Pickup typically takes 5 to 15 minutes. After inserting the SIM, enter the APN settings, using the instructions that come with it.

Mobal

Mobal mainly serves long-term residents, but it has short-stay options too. The data-only SIM is plug-and-play, with unlimited data for 8 days at about 5,500 JPY or for 16 days at about 7,500 JPY. A SIM with a Japanese phone number (voice and data) costs more and suits longer stays. Delivery to your hotel or airport pickup is available.

Pocket WiFi: The Case for Groups and Laptops

A pocket WiFi is a small portable hotspot. One device can serve a family of five and a laptop at the same time, and it usually offers unlimited data under a fair use policy. The downsides are real, though. You have to charge it, carry it and avoid losing it.

• Daily rental: about 900 to 1,300 JPY. Sakura Mobile’s rates start from 900 JPY a day, plus a rental fee and optional insurance.
• Security deposit: may be required, for example 10,000 JPY, refunded on return.
• Optional insurance: about 300 JPY a day.

Book well in advance with a provider such as Japan Wireless (japan-wireless.com), Ninja WiFi (ninjawifi.com) or WiFi Rental Store. Collect it at a dedicated counter or post office pickup point at NRT, HND or KIX, or have it delivered to your hotel. Airport counters can take 5 to 20 minutes at peak hours. At the end of your trip, return it at airport return boxes or designated post boxes.

Free WiFi at Stations and Convenience Stores: A Backup Only

Free WiFi is widespread. Many major JR stations offer “JR-EAST Free Wi-Fi” or similar services after a simple registration. 7-Eleven, FamilyMart and Lawson provide free WiFi, usually after email registration. Cafes such as Starbucks and Tully’s Coffee, museums and shopping malls also have it. The Japan Connected-Free Wi-Fi app helps you find and join hotspots across the country.

Treat it as a backup, because there are limits:

• Speed and reliability can be inconsistent in crowded areas.
• Public WiFi is less secure, so avoid banking and other sensitive transactions.
• You often have to re-register by email each time you connect, or after a set period.

Coverage and Airport Setup: What to Expect on Arrival

Japan has one of the most advanced mobile networks in the world. Docomo, au, SoftBank and Rakuten Mobile provide excellent 4G LTE coverage across the country, including rural areas, JR train lines and many underground subway sections. 5G is expanding quickly in cities and major prefectures. On a Shinkansen window seat, with Mount Fuji sliding past, your map and messages keep working.

Narita, Haneda and Kansai are all set up to handle eSIM activation. Most providers email the QR code, but some offer assistance counters or printed QR codes. With your QR code ready, setup typically takes 5 to 15 minutes. A practical routine is to land, switch off airplane mode, scan the code, then check that data works before you leave the arrivals hall.

2026 Budget Reality: What Connectivity Costs

These are approximate figures based on the prices above.

• Budget (about 1,500 to 1,800 JPY): aHashtag’s 5 GB eSIM for 7 days costs 1,500 JPY. Your Thai carrier’s Asia package costs about 1,800 JPY (429 THB) for 20 GB, which is strong value for a trip of 10 to 12 days.
• Mid-range (about 2,600 to 4,800 JPY): a Thai Global package at about 2,600 JPY (599 THB), aHashtag’s 10 GB for 15 days at 2,700 JPY, Sakura Mobile’s eSIM at 4,400 JPY for 10 GB, or IIJmio’s 10 GB SIM at 4,800 JPY.
• Comfortable (about 5,500 to 7,500 JPY and up): Mobal’s unlimited data for 8 days at 5,500 JPY or for 16 days at 7,500 JPY, aHashtag’s unlimited 30-day plan at 6,000 JPY, or a pocket WiFi at 900 to 1,300 JPY a day, plus about 300 JPY a day for insurance.

For a one-week solo trip, a Thai roaming package is hard to beat on price and convenience. For a month-long trip, or a group sharing one connection, local eSIMs and pocket WiFi often make more sense.

What Changed Since 2024

• eSIM is now the default choice for short-term tourist data, thanks to instant activation and no physical handling. Many new phone models are eSIM-only.
• More competitive pricing and bigger allowances. More eSIM providers and MVNOs have pushed data costs down, especially on plans lasting 15 to 30 days.
• Faster airport service. SIM pickup, eSIM support and pocket WiFi rental are more efficient, with digital kiosks and quicker counters.
• Slight price rises for traditional products. Physical SIMs and Thai roaming packages may be around 5 to 10% higher, often offset by more data or longer validity.
• Pocket WiFi: daily rates are slightly higher, battery life is better on newer models, and returns are more automated at airports.
• Free WiFi: it is more available, especially in smaller towns and local businesses, and some networks have simpler registration.
• No major new rules for tourist SIMs. Buying and activating one still requires passport verification.

Common Mistakes to Avoid

• Landing with no package. Standard roaming without a package can be extremely expensive. Activate before you leave, or the moment you arrive.
• Forgetting the Data Roaming switch. The package is active, but the phone will not use it.
• Ignoring validity periods. AIS’s Asia package lasts 10 days, while DTAC’s and TrueMove H’s last 12. Count your trip days.
• Missing the 128 kbps drop. After 20 GB on the Asia packages, speed falls to 128 kbps. Watch your usage in the operator’s app, especially if you stream video or share a hotspot.
• Relying on free WiFi alone. Repeated registrations, slow speeds and security risks make it unsuitable as your only connection.
• Forgetting your passport. You need it for airport pickup of SIMs and for tourist SIM verification.
• Booking pocket WiFi late. Reserve in advance, and remember the deposit and insurance costs.
• Leaving data roaming on without a package after you switch to a Japanese eSIM. Turn it off on your Thai line to avoid charges.

Frequently Asked Questions

Can I use my AIS, DTAC or TrueMove H SIM in Japan?

Yes. All three Thai operators offer roaming packages for Japan. Activate a package through the operator’s app or a USSD code before departure or on arrival, and turn on Data Roaming in your phone settings. Without a package, standard roaming rates can be extremely expensive.

How much does Thai roaming cost in Japan in 2026?

Approximate 2026 Asia packages cost about 1,800 JPY (429 THB) for 20 GB, valid for 10 days with AIS or 12 days with DTAC and TrueMove H. Global packages cost about 2,600 JPY (599 THB) for 15 GB over 15 days. Prices may change, so check the operator’s app.

Is an eSIM better than Thai roaming for Japan?

It depends on your trip. Thai roaming is simple and keeps your number active. A Japanese eSIM can be cheaper for longer stays, such as aHashtag’s 20 GB for 30 days at about 4,500 JPY. You can often use both, with eSIM for data and your Thai SIM for SMS.

Is pocket WiFi worth it in Japan?

It is worth it for groups, families or anyone using a laptop. One device serves several people and usually offers unlimited data under a fair use policy. Expect about 900 to 1,300 JPY a day, a possible 10,000 JPY deposit, and about 300 JPY a day for optional insurance.

Is mobile coverage good across Japan?

Yes. Docomo, au, SoftBank and Rakuten Mobile provide excellent 4G LTE coverage nationwide, including rural areas, JR train lines and many underground subway sections. 5G is expanding quickly, especially in urban centres and major prefectures, so most travellers will stay connected almost everywhere.

📷 Featured image by Jakob Owens on Unsplash.