Kasai Marine Park

photo by Masahiro Hayata from Tokyo, Japan · CC BY-SA 2.0

Sea swimming in Tokyo lasts six weeks: from 19 July to 30 August, free, 10:00–16:00

In summer, for six weeks only, bathers go into the water in the cordoned-off area of the western nagisa (西なぎさ, the artificial beach open to the public): outside that period, swimming remains prohibited throughout Tokyo Bay. A few hundred metres away, on the eastern nagisa, access is closed all year round: since 2018 it has been Tokyo's first wetland listed under the Ramsar Convention, a refuge for more than 20,000 waterbirds.

The park opened on 1 June 1989 on a stretch of bay reclaimed from the sea, with two artificial beaches (なぎさ, nagisa): the western one, about 830 metres, open to the public, and the eastern one, about 770 metres, a bird sanctuary closed to visitors. It is connected to the nearby Kasai Rinkai Park by the Nagisabashi footbridge.

ℹ️ Free entry. Swimming is permitted only on the western nagisa, from 19 July to 30 August 2026, 10:00–16:00, without booking (Edogawa City sets the dates each year, and they may shift by a few days). The park is open 9:00–17:00 for the rest of the year, with extended hours in high summer. No access to the eastern nagisa at any time of year.

🚉 Kasai-Rinkai Park · 13 min walk

Sources: kasaikaihinpark.com · city.edogawa.tokyo.jp · city.edogawa.tokyo.jp · commons.wikimedia.org

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