The conclusion first: for connectivity, I did nothing. I landed, and the phone was already working.
This is a note for people on a Japanese carrier. I travel on Rakuten Mobile, and what follows is that plan’s overseas roaming — not a general recommendation for every traveller to Thailand.
Arrival, half past three
We reached Bangkok a little after 3:30 in the afternoon. Walking through the terminal, the first thing on your mind is data.
On this trip I simply carried my Japanese Rakuten Mobile line. I never went through the step of buying a local SIM.
There was signal, plainly
And there was signal, plainly. Open the map and your position shows; ride-hailing works, searching works. It felt no different from using the phone in Japan.
Rakuten Mobile’s overseas roaming covers, per the carrier’s own listing, 107 countries and regions as of April 2026, Thailand among them. No separate application is required, and 2GB a month is included at no extra charge. Past 2GB the connection is throttled to a maximum of 128kbps, and you can top up at ¥500 per GB.
So for a trip that does not lean on mobile data, you can leave home without buying anything.
How to think about 2GB
That said, 2GB is small depending on how you use it. Maps and searching will fit. Watch video or upload a lot of photos and you will reach the ceiling in a few days.
In my case I was on Wi-Fi at the hotel and at restaurants, so the mobile line only carried me while I was outside. On that pattern it was plenty.
There is setup involved, and it is worth knowing before you fly: connect to the Rakuten Mobile network in Japan before departure and authenticate the Rakuten Link app there, then switch overseas roaming on from my Rakuten Mobile once you land.
In the car from the airport into the city, the map was already moving. That reassurance counts for a lot. The whole business of hunting for a SIM counter on arrival simply disappears.
Notes
- I carried my Japanese Rakuten Mobile line as-is. No local SIM was bought
- There was signal from the moment of arrival; maps, search and ride-hailing all worked
- Rakuten Mobile overseas roaming: 107 countries and regions as of April 2026 (Thailand included), no separate application, 2GB per month at no extra charge
- Beyond 2GB the speed is capped at 128kbps; top-ups are ¥500 per GB
- Device setup is required — connect to the Rakuten network and authenticate Rakuten Link in Japan before departure, then turn on overseas roaming after you land
- Combined with hotel and restaurant Wi-Fi, 2GB is workable
- If you are not on a Japanese carrier, this does not apply to you; a travel eSIM or a local SIM is the usual route
- Pricing, covered countries and conditions change. Check the carrier’s own information before you fly
Travelled August 2025. Pricing and service terms are based on the carrier’s published information at the time of the trip and at the time of writing.
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