Copenhagen's harbour is about to get its most ambitious swimming spot yet. Kai, a 62,500-square-foot public bathhouse designed by Japanese studio Kengo Kuma Associates, opens on Saturday 5 December on Paper Island, right across the water from Nyhavn. Entry is expected to cost under 100 Danish kroner — roughly $10 — in line with the city's other municipal pools, which is remarkable given the building's pedigree.
The project has been eight years in the making and carries a price tag of 989 million DKK (about $150 million), funded by the City of Copenhagen and Nordea Fonden. Pandemic delays pushed the opening back from 2021. Inside, ten pools are spread over several levels, including an 82-foot pool on the ground floor, an open-air rooftop pool, and a heated onsen-style bath overlooking the harbour. An outdoor first-floor pool is warmed year-round by a sustainable vertical ground-source heat pump, so winter dipping won't require courage quite as much as usual. Capacity is capped at 380 swimmers.
The location is part of the appeal. Paper Island, once home to a much-loved street food market and empty for years, is being redeveloped with restaurants and cafes. The idea came from Copenhageners themselves — surveys showed demand for a central public pool — and the site links the old town with Holmen, the former military quarter, and Refshaleøen, the old shipbuilding district. A pedestrian and cycle bridge connects it to the centre. Architecturally, Kai slots into a distinguished line-up that includes the Opera House and the Royal Danish Playhouse.
Swimming is woven into Copenhagen life. The harbour's floating pools appeared in the early 2000s after the shipyards closed, turning industrial water into a public playground, and cold-water plunging has since boomed — winter swim clubs with sauna access now have long waiting lists.
If Kai sparks your interest, the harbour has more to offer. At Sandkaj in Nordhavn you can swim lanes directly in the deep harbour (bring your own changing arrangement; the facilities are members-only), then warm up at Saunanor, where you can try saunagus, a Danish ritual of intense, aromatherapy-laced sauna sessions. For something more spa-like, Skodsborg Spa Hotel up the coast occupies a former sanatorium and offers 16 bathing experiences plus a private swimming jetty on the beach. Valby's Water Culture House, a stylish grey building with a slide, lane pools and a hot pool area, is another good public option.
Kai matters for travellers because it turns a rainy-day or winter city break activity into something genuinely special at a local price. Most capital cities make you pay spa rates for a swim with a view; Copenhagen is doing it for the cost of a coffee and a pastry. Pack the swimsuit.
Condé Nast Traveler
