Tokyo: signal everywhere, except two tunnels and one mountain

The city where an offline phone genuinely hurts

Tokyo has 48 rail operators running more than 100 lines. Nobody works that out from a paper map on arrival. Google Maps does it, Suica pays for it, and both want a live connection. That is the case for data in Tokyo, and it is a stronger case than in most cities — not photos, not messaging, but getting from one place to the next at all.

The reassuring part is that the network almost never lets you down here.

Signal: excellent, with two exceptions

5G covers all 23 wards. Average 4G speed is around 55 Mbps, and Shibuya and Shinjuku regularly measure 400–500 Mbps on 5G. Asakusa, Akihabara, Harajuku and Odaiba are all strong. Most subway tunnels on the major lines carry 4G.

Two places it does fail:

• The oldest subway lines. The Marunouchi and Ginza lines lose signal in their deepest tunnel sections.
• Mount Takao. On the standard day trip west of the city, the upper trails have gaps above a certain height.

For essentially everything else a visitor does here, you have signal continuously. Which carrier you end up on is not a Tokyo question — every network is strong across the city. That is emphatically not true of rural Hokkaido or the Okinawan outer islands, so if Tokyo is one stop on a longer trip, decide the network question against the other stops rather than this one.

What a Tokyo trip costs

These prices were read from the providers' own sites on 13 August 2026.

For a three-to-five day city break spent on Maps, messaging and photo backup, 1 GB is genuinely enough. A standard week is a 3 GB plan. If you lean on Translate's camera mode all day or post video, go to 5 GB and stop thinking about it.

Worth knowing where the ladder ends. This page used to say Japan's metered plans topped out at 20 GB; they do for Airalo and Saily, but not for Nomad, whose 50 GB for 30 days at $35 is a verified $0.70 a gigabyte and the cheapest data in the country. Above that you are buying unlimited, and Airalo's 30-day unlimited is $69 — a different order of spending. Prices we hold for Holafly and eSIM Go have not been read off their own sites, so treat those as indicative; eSIMCard's have been withdrawn.

Buying a physical SIM in the city

Haneda (HND) is far closer to central Tokyo than Narita, and if you land there the Docomo counter is in Terminal 3, with a queue of roughly 10 to 15 minutes.

In town, Bic Camera at Yurakucho or Akihabara and Yodobashi Camera at Akihabara both sell prepaid SIMs, and both have English-speaking staff who will set the SIM up with you at the counter. That is worth more than it sounds if you have never configured a Japanese APN by hand.

Bring your passport either way — Japanese prepaid SIMs require ID to register. Our figure for a Japanese airport SIM is about $12, close enough to eSIM money that the only real question is whether you want to queue on landing.

Two seasons when the crowd is the problem

Cherry blossom season, late March into April, slows the network at Shinjuku Gyoen and Ueno Park; the crowd is concentrated in a small area and everyone is uploading at once. Golden Week, late April into May, congests Shibuya, Shinjuku and Asakusa. Neither breaks anything, but save your offline map before heading to a crowd spot in either window.

Full plan comparison across every provider is on the Japan hub.