Koster Islands & Kosterhavet

Boats leave the pier at Långegärde on Sydkoster, beside the ferry landing, and the ride out to the sites in the Koster archipelago takes about five minutes. The island centre keeps its groups small and dives only inside Kosterhavet. A centre in Grebbestad also runs daily dive trips into the park through the whole year, so boats are out in winter as well as summer. Yttre Vattenholmen is very exposed and takes a lot of swell, while Krugglö still works in a strong wind.

The Kosterfjord, 200 m deep, brings deep North Sea water into the archipelago, and the fjord stays at 5 to 7 °C with high salinity. Around the skerries the dives follow classic west-coast cliffs and walls down to shell gravel, sand and boulder fields at around 30 m. On the walls, dead man's fingers and plumose anemones crowd the rock, with squat lobsters, edible crabs and decorator crabs among them. Where water exchange is poor, as at Östra Långholmen, algae and mud-bottom animals take over.

The skerries suit divers comfortable in cold water who come for anemone-covered walls and the small crustaceans living on them; divers after warm water should look elsewhere. Inre Vattenholmen, Krugglö and Östra Långholmen are easy dives, while Yttre Vattenholmen and Nordöskär are medium. In summer the motorboat traffic around Yttre Vattenholmen is heavy, and dives there are made under a flag.