Project Fi or Tmobile use in Japan

Has anyone used PFi or Tmo in Japan with great or at least good reception? If so, which network company does it use, Docomo, Softbank, etc? How are the speeds? Does it work underground like in stations?

I was thinking of renting a pocket wifi but if Pfi or Tmo speeds are pretty good in the major city then I can save some money and use those services instead of renting. Both Pfi and Tmo have hot spot capabilities. If service isn't all that great or a hit and miss, I'm willing to rent.

I previously used both when I vacationed in the Philippines last year. It was a hit and miss. Metro-Manila had high speed. But where my family was up north, had various speeds from LTE in certain parts of the city and 2G/3G/E. Also went to Coron, and out on the ocean in between islands was able to get LTE and some lower speeds.

Places I'll visit:
Tokyo/Kyoto/Nara/Hiroshima/Miyajima/Takayama/Shirakawa-go/Kanazawa/Yokohama/Enoshima/Kamakura

I've used Fi quite a bit in Japan. I don't think network speeds are supposed to be great (pretty sure I read somewhere it's throttled,) but for my usual web/chat/gmaps it was never a hindrance. Connection was LTE for the most part, though there were times when it dropped into 3G when my reception was bad (always indoors or rural.) Works fine in underground stations and subways. I don't recall which network it was connecting to, but whatever it was it has good coverage. Definitely not an issue in major cities, and pretty good even in rural areas. I don't think you'll get appreciably better coverage with a rental, though you will probably get higher top end speeds. Note that the above is with a Nexus 6P - I think all the Google phones cover the same radio bands, but your experience may differ with a different phone.

@ gfoulk

Thanks. I have the 5x.

When was the last time you visited Japan with Fi? I've read that some people had mixed results since the latest update. Some said they had problems getting service. It took them about half an hour to several hours. Some said even days before they got service. These people have used Fi previously in Japan so they were confused on why all of a sudden it no longer worked.

I think I might just rent a portable data wifi for peace of mind. I would need it for navigating purposes mainly (gps, mapping, etc), social media updates, emails, backing up photos and so on. I have a feeling my data usage will equal out or be more than renting a pocket wifi for my whole stay.

I was last in Japan in October 2016.

If you expect to use more than a couple gigs of data, yeah, renting a unit may be cheaper anyway.

I'm currently in Japan on Project Fi with a 6P and it's working great. LTE everywhere I've been so far (Tokyo, Yokohama, Nikko) with no dead spots at all, including the trains. Not sure which network it's on, though I have a data-only SIM on another device that is connecting to SoftBank. Speed seems fine on that, too.

Of course, depending on how much data you're planning to use it might still be worth it to rent a pocket wifi. I'm mostly on wifi here, so I don't have a huge need to rely on Fi.

I used Fi with a Pixel this past December in Japan. It doesn't really say which network you're connected to, it just says "Fi". Maps, internet browsing, and email works fine when I'm out and about. No noticeable lag. My cities included Tokyo, Hakone, Kyoto, and Hiroshima. Have not tried in the super rural areas.