Japan is one of the easiest countries in the world to travel in, and almost all of that ease lives on your phone. Suica in your wallet, Google Maps for the metro, translation for menus, and train timetables that change by the minute. Without data, Japan gets hard fast.
Here's how to arrive connected, what coverage to expect, and how the costs stack up.
The short version
Japan's networks are among the best in the world. You'll have 5G in cities and 4G almost everywhere else, including on the shinkansen.
A 10GB Japan plan valid for 30 days is A$18.45. The 3GB plan is A$5.45 if you're only there a few days.
Install the eSIM at home on Wi-Fi. Don't buy at the airport.
Set up Suica in Apple Wallet or Google Wallet before you leave. You'll need data to top it up.
Coverage and speed
Tokyo, Osaka, Kyoto, Fukuoka and Sapporo all have dense 5G coverage. The shinkansen network has continuous 4G, including in tunnels on the main Tokyo to Osaka line. Subways in Tokyo and Osaka have coverage on the platforms and in the tunnels.
Rural Japan is better than rural Australia. You'll find 4G in most towns, on hiking trails near cities, and on the ski fields in Hakuba and Niseko. The places it drops out are deep mountain valleys and some remote coastal roads, which is also where the JR trains stop running.
Roamly's Japan plans connect to NTT docomo, KDDI au, SoftBank and Rakuten Mobile, all on 5G, so you get the same towers as a local SIM. Docomo has the deepest rural coverage and is the one you'll usually land on outside the cities.
Why data matters more in Japan
Suica and transport. Adding Suica to Apple Wallet or Google Wallet, topping it up, and buying shinkansen tickets on the SmartEX app all need data. Tapping through gates works offline, but you'll be topping up constantly.
Google Maps for trains. It's the best transit app for Japan and it knows platform numbers, transfer times and which carriage to be in. Download an offline map of each city as a backup.
Translation. Google Translate's camera mode for menus and signs, and voice mode for conversations. Download the Japanese language pack before you go so it works offline too.
Restaurant bookings and Tabelog. Many places only take reservations through apps or LINE.
What it costs
Roamly's Japan plans at the time of writing:
For a typical 10 to 14 day trip, 10GB suits most people. If you'll be uploading a lot of video or hotspotting a laptop, go 20GB. Plans are reloadable, so running low mid-trip isn't a problem.
Versus the alternatives
Carrier day pass: around A$10 a day from Telstra, so A$100 to A$140 for two weeks, with a small daily data cap.
Pocket Wi-Fi: typically A$8 to A$12 a day, plus a device to carry and charge and a return process at the airport. Fine for a family sharing one connection, but hotspotting from an eSIM does the same job.
Airport SIM: available at Narita, Haneda and Kansai, but pricier per gigabyte and you'll queue for it. Some tourist SIMs are data-capped at speeds that make video calls painful.
Setting up for Japan
Check your phone supports eSIM and is unlocked.
Buy your Japan plan and install it on Wi-Fi before you fly. Follow the installation guide if you haven't done it before.
Add Suica to your phone wallet while still on home Wi-Fi.
Download offline Google Maps for Tokyo, Kyoto and anywhere else you're going.
On landing, switch mobile data to the eSIM and turn on data roaming for that line. Turn data roaming off for your Australian line.
A few Japan-specific notes
Your Australian number keeps working for calls and texts, including bank codes, as long as the SIM is in the phone. Use LINE, WhatsApp or FaceTime over the eSIM for calls home.
Free Wi-Fi is everywhere but slow. Convenience stores, stations and hotels all have it. It's useful for backing up photos at night, not for getting around.
Hotspotting is included, so one Roamly plan can cover a travelling partner's tablet or laptop.
See Japan eSIM plans, or work out how much data you'll need for your trip.