Nihongaishi Arīna | 日本ガイシ アリーナ

This is a really a nice facility. And only one to three swimmers per lane when I was there. Other swimmers moved out of my lane when I started coming up behind them. (If you didn't already know, there is no passing allowed in most pools in Japan.)

Superb facility. I swam in the 50m pool, which has one lane reserved for walking. There were only two or three swimmers per lane on the Saturday morning I was there. Clean changing room with showers. Lockers available for a ¥100Y coin, which is returned when the key is used to re-open locker. The pool is cleared (no swimming) for 10 minutes at the top of the hour, which is standard operating procedure in Japan.