Okinawa: the coverage question changes with every ferry

One prefecture, 160 islands, 400 km of ocean

Okinawa is not a city and it is barely one place. It is a prefecture spread across 160 islands over 400 km of ocean, and what connectivity means here depends entirely on which of them you are standing on. The main island behaves like the rest of Japan. The far southern islands do not, and one of them is among the worst-connected places in the country.

The main island is ordinary, good Japanese coverage

Naha city, Kokusai-dori and Shuri Castle all have solid coverage, and the Churaumi Aquarium up in the north is good. Average 4G runs around 35 Mbps — the lowest of the Japanese places we cover, against 55 Mbps in Tokyo — and comfortably more than enough for maps, booking and messaging.

If your trip is Naha and the main island, stop reading and buy on price. Any provider works.

Ishigaki, Miyako, and the water in between

The southern islands are why people fly on past Naha: clear water, good diving, and busier every year.

• Miyako-jima — the main town and the beaches near it are fine. The remote beaches on the eastern and southern coasts are patchy.
• Ishigaki — town and resort areas are good.
• The Taketomi ferry — a seven-minute crossing from Ishigaki, and the signal drops in the middle of it. Trivial on its own, but a fair warning about how fast coverage ends once you leave land here.

Ferry crossings and remote beach roads are where the gaps sit. Nothing on these two islands is remote enough to be dangerous, but "I will look up the return timetable from the beach" is a plan that fails.

Iriomote is genuinely offline

Iriomote, reached by ferry from Ishigaki, is one of Japan's last wild islands — mangrove rivers, UNESCO-listed jungle, rare wildlife — and one of the worst-connected places in Japan. The main port area has signal. The interior has essentially none, and no carrier changes that.

Download everything before you go in: maps, tour details, ferry times, the address of wherever you are sleeping. This is the one place in Okinawa where that is not a convenience.

Which network, and why we will not sell you one

NTT Docomo has the widest reach across Okinawa's outer islands. It is not perfect — Iriomote's interior defeats everybody — but it gets further into marginal areas than the alternatives.

That would be a clean recommendation if travel eSIMs told you which network they roam onto. Mostly they will not. Airalo does not publish a host carrier for any country, and the values we hold for other providers were never confirmed against their own sites, so we will not rest an island-hopping recommendation on any of them. If Docomo's reach is what your trip depends on, a Japanese prepaid SIM bought from that carrier is the only version of this you can verify for yourself. Bring your passport; Japanese prepaid SIMs require ID to register.

Naha Airport, and what to buy

Naha (OKA) handles both international and domestic traffic but has limited SIM counter options next to Narita or Haneda. If Okinawa is your entry point to Japan rather than a domestic hop, arrive with an eSIM already installed rather than counting on a walk-up purchase.

Read from the providers' own sites on 13 August 2026:

A beach-and-diving week gets through less navigation data than a city trip and more photo and video upload, which tends to net out about even; 5 GB covers a fortnight for most people. Airalo and Saily stop at 20 GB for 30 days in Japan; Nomad's verified 50 GB month at $35 is the one plan above that, at $0.70 a gigabyte. Figures we hold for Holafly and eSIM Go are indicative rather than checked, and eSIMCard's have been withdrawn.

Full comparison across providers is on the Japan hub.