Kostersten

Kostersten is an advanced dive site on Sweden's west coast near the Koster Islands, where the proximity to Sweden's first national marine park creates diving in some of the most biodiverse waters in the entire country. The Koster area, at the border with Norway, sits where deep Atlantic water enters the Skagerrak, supporting marine communities of exceptional richness. The underwater landscape at Kostersten features the granite formations and deep-water access that make the Koster area unique in Swedish diving. The proximity to deep water means that species normally found far offshore can be encountered at diveable depths, creating encounters unavailable at other Swedish dive sites. Cold-water corals, rare sponge species, and deep-water invertebrates add genuine scientific interest to the diving. The rock surfaces support extraordinarily dense communities of filter-feeding organisms. The current-swept conditions and nutrient-rich water create biological growth of impressive density, with anemones, soft corals, and sponges covering every surface. The diversity of species present reflects the Koster area's status as Sweden's most species-rich marine environment. Fish diversity is enhanced by the deep-water influence, with species from multiple habitats represented. Cod, pollack, and wrasse form the core community, supplemented by deeper-water species that venture into the shallower zones from the adjacent depths. Lobsters and crabs are commonly encountered in the rocky terrain. The advanced classification reflects the exposure to currents, the depth available, and the open-water conditions that characterize this stretch of coast. The Koster area's national marine park status ensures ongoing protection for its exceptional marine communities. Kostersten delivers the pinnacle of Swedish cold-water diving, where the convergence of Atlantic water and Nordic coastline creates a marine environment of national significance.