[Nagoyankee]

Public bath houses （銭湯） - No Problem. I don't know why some people have said otherwise. I see guys with much more elaborate tattoos (practically all over their bodies except faces) in these places.

Hot Springs - Problem. But most hotel rooms in hot spring resorts have a private bath in the room.

Swimming Pools - Mostly Impossible. There are exceptions such as the Tokyo Summer Land for one.

Pools at hotels - Utterly impossible.

Beaches/Rivers/Lakes - No problem whatsoever.