Copenhagen's Paper Island gets a major new attraction on 5 December 2026: KAI, a 5,800-square-metre public bathing and wellness complex designed by Japanese architect Kengo Kuma. The name works in both languages — 'kai' means sea in Japanese, 'kaj' means quay in Danish.

The idea came straight from locals. In 2015 the city asked Copenhageners what they wanted done with Paper Island in the inner harbour, and a public swimming facility topped the wish list. An international design competition followed, and Kengo Kuma & Associates won it, working with Cornelius Vöge Atelier for Architecture and Vilhelm Lauritzen Architects on the final building.

What visitors get is generous: ten indoor and outdoor pools, three saunas, a heated stone, a steam bath and various cultural spaces, all wrapped in a building with 403 windows overlooking the harbour. The ground floor is fully glazed and houses a fitness pool, a teaching pool and three children's play pools. Above it, five brick towers — built from around 300,000 handmade bricks — rise over the pools they shelter.

Two features stand out. The outdoor Valley Pool sits between the brick towers, letting swimmers bathe under the open sky through all seasons, while a heated Onsen offers panoramic views across the harbour. A separate swimming and dipping zone along the waterfront, linked by a timber boardwalk, is due to open in early 2027.

Better still, this is not a luxury spa with luxury prices. Admission matches Copenhagen's other municipal swimming facilities, and the indoor section runs 6am to 9pm daily. The harbour dipping zone stays open around the clock, all year.

City officials hope KAI becomes a new gathering point for swimmers and visitors alike, a civic landmark in a spot the city has spent a decade converting from industrial port to public waterfront. For travellers, it slots neatly into a Copenhagen itinerary that already leans heavily on harbour life — swimming in the inner harbour has been a thing here for years, and KAI gives it a proper year-round home.

Practical note: Paper Island (Papirøen) sits right in the inner harbour, an easy walk or short cycle from Nyhavn, so pairing a dip with the street food hall and a harbour stroll makes for an easy half-day. If you're visiting Copenhagen from December 2026 onwards, budget an hour or two for KAI — at municipal prices, it might be the best-value view in the city.

Story reported by Travel Tomorrow.