Japanese people loves to soak in warm spring water baths called Onsen. They are an amazing option to stay clean while travelling by camper in Japan but it's not the only one.

Onsen

Japan has a ton of onsen across the country. An onsen is an hot spring bath, the cost to access it can range from 200 to 1000 JPY. Showers or cleansing areas are found in between the changing area and the actual onsen. Sit on small stools and wash with the shower or small bucket provided and make sure there’s no trace of soap left. You can then enjoy the bath and rinse after.

Some big hotels or traditionnal inns (ryokan) that have onsens allow "higaeri onsen" (day-trip hot spring). You can enjoy the onsen of the hotel without being a guest here.

You should note that many onsens prohibit people with tatoos from visiting them.

Kaikatsu clubs

Kaikatsu Club is a major Japanese internet cafe chain that offers a variety of relaxation and entertainment services, including private rooms, computers, manga, and sometimes amenities like karaoke, billiards, and showers. It's a popular spot for budget travelers, students, and locals who need a place to relax, work, or even spend the night in a private, secure space. They can be used just as a shower place. Kaikatsu clubs are fantastic you can be in and out in 15 minutes and cost ¥200-300 each.

Beach shower

Some of the beach toilets offer showers (paid or free). They are usually only open during the summer season (but might be open year long near surf spots).

Campgrounds

Most campgrounds do have showers and some even have partnership with close by onsen.

Pools

Public pools can be a good option to get a shower and bath around big cities.