The Glynn Vivian in Swansea city centre is Wales’ oldest public art gallery and its own visitor page states free admission. The collection spans Old Masters, Swansea porcelain, Welsh modernism and contemporary work, with a regularly changing exhibition programme.

Last entry is at 4pm. The building has a cafe, a shop and an art studio space, and sits within easy walking distance of the city centre and the marina.

Nothing to book and nothing to pay – just turn up during opening hours.