After some searching, I was able to join a few local groups and wanted to share in case others were interested!
For Racquetball, there's only a few courts throughout tokyo. The one I joined is in Chofu https://maps.app.goo.gl/GyGwauTn8Vq5wh9w9 with 2 courts and has a ~2.4k yen visitor fee. You can make a 30 minute reservation for a court day of on a sheet next to the courts, but most people seem friendly and are willing to play pickup. For official tournaments, the main org appears to be http://jara-npo.org/ and you may be able to find additional court information through them (one in yokohama, I've heard something about YMCAs too)
For Pickleball, I emailed the pickleball japan federation here https://pickleball-japan.org/contact and there were able to bring me into contact with a few local groups. There's a per-neighborhood based TeamReach group chat (Shibuya, Shimokitazawa, etc) and by talking to the main host of a group you may be able to find more groups in your neighborhood. The groups I'm in play a couple of times a week (split across morning/afternoon/evening), require app reservations, and have a small fee per session (~300 yen). Sometimes the venue is the gym of a local school or a court at a recreation center.
For both groups, the primary membership base are Japanese retirees with a handful of younger folks. The primary language is Japanese but a couple of people usually know some english too. Skill level varies from beginner-advanced.
Hopefully someone finds this helpful!
by ecmmmeee
