Kengo Kuma's KAI Water Culture House bathhouse opens on Copenhagen's Paper Island

This one began with the public. In 2015 a city-led ideas competition drew 160 proposals for Copenhagen's Papirøen, or Paper Island, and most asked for somewhere to swim. Kengo Kuma & Associates won the architectural competition in 2017, and the result, KAI Water Culture House, is due to open on 5 December 2026: a 5,800-square-metre spa with ten pools on a harbourfront that has been shifting from industry to leisure.

You'll know it by its five irregular brick towers rising above a band of glass, so the heavy masonry seems to float. Each tower takes its shape from the pool beneath it. Around 300,000 handmade bricks in harbour greys are laid in a stepped pattern that catches the light, pierced by 403 windows of varying sizes. The tallest, the Culture Tower, will host cultural and community events.

The standout is the Valley Pool, an open-air basin on the first floor between the towers, sky overhead. Beside it, a heated onsen looks out over the harbour, and both run all year on ground-source heat. Downstairs are a 25-metre fitness pool, a teaching pool and three children's pools; upstairs, warmer baths, a cold plunge, saunas and a steam bath.

A timber boardwalk to harbour swimming spots facing the Royal Danish Playhouse and Opera Park should follow in early 2027. Worth planning a winter swim around.

Our summary of a story from designboom, published 28 October 2026. Read the original

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