Kosterhavet National Park
Sweden's first marine national park - clear cold waters and coral reefs around the car-free Koster islands on the border with Norway.
Updated 16 October 2026

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Kosterhavet is Sweden's first marine national park, protecting the unusually clear, cold and biodiverse waters of the Kosterfjord on the border with Norway, home to cold-water coral reefs and hundreds of marine species found nowhere else in the country. Above the water lie the car-free Koster islands, a summer world of cycling and bathing.
Background
Kosterhavet, the Koster Sea National Park, was inaugurated in September 2009 and lies in the Skagerrak within the municipalities of Strömstad and Tanum in Bohuslän. It covers the sea and shores around the Koster Islands, about 400 square kilometres, but leaves out the rest of the islands themselves, and to the north it meets the Norwegian marine park of Ytre Hvaler. Over 6,000 marine species have been recorded here, about 200 of them not found elsewhere in Sweden, and the park holds the country's largest seal colony. It has five entrances, an exhibition and a touch aquarium, and about 90,000 people visit.
Source: Wikipedia, "Kosterhavet National Park"
What you'll find
- The marine reserve - the clear cold waters, coral reefs and rich sea life.
- The Koster islands - the car-free islands of Nordkoster and Sydkoster.
- Cycling and bathing - the island lanes, coves and rocky swimming spots.
- Seafood - the local prawns, lobster and oysters of the west coast.
When to go
Summer, when the ferries run full, the islands are alive and the water is warmest for swimming; it is a warm-season destination. Autumn brings the seafood season and quiet.
Before you go
The marine wonders are mostly underwater, so unless you dive or snorkel, the appeal above water is the pretty car-free islands and their seafood. Access is by ferry only, so it needs planning. It is far up the west coast near Norway, a real journey.
Nearby
Stromstad is the mainland gateway; the Norwegian border and the Bohuslan coast are alongside.
Key facts
Source: Wikidata, item Q1438951, read on 18 October 2026.
What to pack for Kosterhavet National Park
Chosen from what this place is for. Tap a kit for the full checklist.
- Broken-in walking shoes or boots - Grip and ankle support matter more than looks; never hike in brand-new boots. Find on Amazon
- Reef-safe sunscreen - High SPF that will not bleach the coral you are swimming over. Find on Amazon
- Your own mask + snorkel - A well-fitting mask is the single biggest comfort upgrade underwater. Find on Amazon
- Padded shorts - The one thing that makes a full day in the saddle bearable. Find on Amazon
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Opening times, ticket prices and seasonal closures change - check the official source before you go: official site.



