Live /japan 10 GB rows for 30 days, cheapest first after Maya is removed and Yesim falls to seventh: Nomad $16, Sim Local $16.50, Ubigi $16.50, GigSky $16.79, Saily $17.99, Airalo $18. A named host on the shop or SKU splits a tie only when two of those 10 GB totals are the same. Sim Local and Ubigi meet at $16.50; Sim Local is cheaper at 5 GB ($11), and Ubigi has no 5 GB 30-day country row.
Opensignal's Japan Mobile Network Experience Report, April 2026 (90 days from 1 January to 31 March 2026), covers au, NTT docomo, Rakuten Mobile and SoftBank. au took ten sole awards and one joint award, including a clean sweep of the experiential metrics. Download Speed Experience: SoftBank 65.1 Mbps (sole). Upload Speed: Rakuten Mobile 15.8 Mbps. 5G Download: NTT docomo 159.1 Mbps. 5G Upload: Rakuten Mobile 23.8 Mbps. Consistent Quality: au 88.3 per cent. Reliability: au 967 (100 to 1000). Coverage Experience: NTT docomo 9.0 (0 to 10). 5G Coverage: NTT docomo 5.0. Time on Network: au and NTT docomo 99.7 per cent, joint. Time on 5G: SoftBank 27.4 per cent. Video Experience: au 74.1. The same report notes MIC applications for 26 GHz mmWave, with an auction later in 2026, NTT docomo's 3G FOMA shutdown on 31 March 2026, and nationwide emergency JAPAN Roaming from 1 April 2026. TCA's English FY2026 table prints a mobile-telephone total of 232,875,800 at 1Q June 2026; per-carrier HTML cells were not retrieved this pass. Those scores describe the four national MNOs. They do not name a host for any pick.
Japan is not in a roam-like-at-home bloc with South Korea or Taiwan. A Japan-country plan stays inside the storefront's Japan coverage. Korea and Taiwan stay empty on the Japan-country SKUs unless that shop names a latch; none of the six did this pass. Ubigi's Asia 10 GB 30-day dest row is a different SKU ($42).
Island and territory cells stay empty unless that shop or SKU names the place. Airalo's Moshi Moshi 10 GB 30-day payload other_info says it covers all of Japan, including Okinawa and Hokkaido. That list is Airalo Moshi Moshi-only. Nomad's Japan shop warns that coverage may not include overseas territories and markets Tokyo and Osaka. Sim Local 5/10/20 GB country SKUs print coverage as Japan and do not name Okinawa or Hokkaido. Ubigi 10 GB and 25 GB SKUs do not name them. Yesim's country shop city list is Fukuoka, Kawanakajima, Kobe, Kyoto, Nagoya, Osaka, Saitama, Sapporo, Tokyo, Yokohama, and other cities in Japan. Sapporo on that list is not a Hokkaido coverage line. Saily names Tokyo, Kyoto, Osaka, Fukuoka and Sapporo, and prints rural Hokkaido as patchier for any carrier. Do not infer Okinawa, Hokkaido, Kyushu, Shikoku or Tsushima from KDDI, SoftBank or Docomo.
The live /japan order at 10 GB for 30 days is Nomad, Sim Local, Ubigi, GigSky, Saily, Airalo. Top-ups sit in each provider's app once the plan is on a Japanese network.
Suica or ICOCA already loaded and the Shinkansen seats already booked: skip to the plans. Still sizing nights against gigabytes for a city hop versus a countryside stretch, Plan Match at /plan-match ranks the live country table from both answers.