Flora and fauna

For those interested, Koster is a paradise.
On Koster you can experience a rich and varied nature – from heaths and vast pebble fields on North Koster to the lush landscape of South Koster with deciduous forests, flower-rich dry meadows and inviting beaches. The Koster Islands Nature Reserve is surrounded by Sweden’s most species-rich marine area, the Kosterhavet National Park. Feel welcome to visit the Kosteröarnas nature reserve.


Koster’s calcareous soil, dry and sandy soils and sunny climate provide good conditions for a particularly rich flora and inventories show more than 600 species of vascular plants. Here you will find several different species of orchids and rare plants such as the Bohus rush, the martorn and the sand thyme.

At Ekenäs on South Koster stands an old coarse bohuslind, one of Sweden’s most unusual trees.


The flowering herbs and grasses of the islands attract a large number of butterflies and other insects. Birdlife is also varied, with mergansers and thornbills thriving in open fields and shorebirds such as terns, eiders and shorebirds often seen on the shoreline.

Good to know; the Koster Islands are largely a nature reserve, which means certain restrictions, such as not bringing rocks or digging up plants. in addition, dogs must be leashed. Tents are not allowed on the islands, except on designated campsites.

Download the nature reserve brochure