2026 Sarue Onshi Park Splash Pond: A Full-Day Course

In Sarue Onshi Park in Koto City there is a free summer-only water play area, the Sarue Onshi Park Splash Pond. The 2026 season runs from July 1 (Wed) to September 30 (Wed), from 10:00 to 16:00, with the water switched off from 12:00 to 13:00. It is closed every Monday and on July 21 (Tue), and may be cancelled during typhoons, in rainy weather, or on days when the temperature is below 25C. The venue is Sarue Onshi Park in Koto City. Built on land that was once a timber storage yard of the Edo shogunate, it is divided into a north garden and a south garden, where lawns and groves create greenery you would not expect in the middle of the city. Admission is free and there are toilets in the park. There are no changing rooms or showers, so wearing swimwear underneath is by far the easiest approach. In the morning you visit Sarue Shrine in Sumiyoshi, then head on to Kameido Tenjin Shrine, known for its wisteria. At lunch you spread out a bento on the park lawn, and in the afternoon you head to the splash pond as it starts up again. With the Hanzomon subway line and the Toei Shinjuku line both available, this day links a tour of old downtown shrines with water play.