Five brick towers, each shaped by the outline of the pools below, rise above a glass base on Paper Island in Copenhagen, where KAI Water Culture House by Kengo Kuma & Associates is due to open on 5 December.
The idea came from Copenhageners themselves. When the city held an ideas competition for Papirøen, Paper Island, in 2015, it received 160 proposals, and most of them asked for somewhere to swim. Lord Mayor Sisse Marie Welling puts the case in five words: “Copenhagen needs more swimming facilities”. An international competition followed in spring 2017, and Kengo Kuma & Associates won it, with Yuki Ikeguchi as partner in charge. Cornelius Vöge worked on the scheme through the concept stage; Vilhelm Lauritzen carried it from detailed design to completion.
The client, Ejendomsfonden Vandkulturhuset Papirøen, built it for DKK 989 million, with DKK 546 million from Nordea-fonden and DKK 443 million from the City of Copenhagen. The result covers 5,800 square metres. Its 300,000 handmade bricks vary subtly in shade and are laid in a staggered, stepped pattern; KAI says their colour follows the greys of the buildings around it. There are 403 windows of different sizes, each framing a view and letting daylight in. The tallest of the five is the Culture Tower, with rooms for culture and movement and space for the city’s clubs and associations to meet.
Ten pools hold a million litres between them. The ground floor has a 25-metre pool at 27°C, a teaching pool at 29°C and three children’s play pools at 32°C. The wellness pools are on the first floor, a 36°C therapy pool, a 42°C hot pool and a 15°C cold plunge, alongside a heated stone, a steam bath and three saunas. Two more sit outdoors on that level: the Valley Pool, set between the brick towers and open to the sky at 26°C, and the Onsen, at 36°C, looking out over the harbour. Ten boreholes, drilled 250 metres down for a ground-source heat pump, keep both heated through the year.
Outside, a timber deck runs along the quay with two areas marked out in the harbour itself: a 12 by 50 metre swimming zone facing Opera Park and a 6 by 22 metre plunge zone in front of the building, looking across to the Royal Danish Playhouse. Deck and harbour bath will be public around the clock, all year, but they will not be finished in time for December and follow in early 2027. KAI has a capacity of 380 bathers and keeps hours of 6:00 to 21:00 every day, at prices set in line with the city’s other pools.
Ikeguchi sets the project inside a longer change: “It is part of the ongoing transformation of the city and its harbour from an industrial port into a cultural waterfront, where new functions have helped bring the surrounding areas of the Inner Harbour to life.” The name is built from both languages. In Japanese, kai is the sea; in Danish it calls up kaj, the quay the building stands on. KAI stays shut while the builders finish, and opens on 5 December 2026.
