Tominoyu Public Bath (富の湯) — Komae 富の湯
Live-action filming location. It is a recurring location: episodes 1–6 and 8 of the first season, episodes 1–3, 5 and 8 of the second, and the bathhouse has confirmed its cooperation with the filming on its official social media channels. About 450 m away, Minowada Bridge over the Nogawa River (箕和田橋) is the little bridge that appears again and again in the transition scenes of both seasons.
A historic public bath in Komae.
Tokyo
Chofu, Kokuryo
Kotaro Lives Alone
Live-action filming location. It is a recurring location: episodes 1–6 and 8 of the first season, episodes 1–3, 5 and 8 of the second, and the bathhouse has confirmed its cooperation with the filming on its official social media channels. About 450 m away, Minowada Bridge over the Nogawa River (箕和田橋) is the little bridge that appears again and again in the transition scenes of both seasons.
All the places from Kotaro Lives Alone
https://theanimetrip.com/luoghi/bagno-pubblico-tominoyu-komae