Kasthúsatjörn supports rich biodiversity and abundant birdlife. The shoreline and surrounding coastal waters are particularly well suited to nature exploration, including birdwatching and exploring the shore.
Protection Status
Part of Kasthúsatjörn and its surroundings on Álftanes was designated a nature reserve in 2002. The designation protects this shallow coastal lagoon and its rich ecosystem, particularly its diverse birdlife.
The shoreline adjoining Kasthúsatjörn was designated a country park in the same year. The purpose of the designation is to preserve the area for outdoor recreation and public use.