The Tilsler Island is characterized by bare rock and heath, but in sheltered areas there is rich and varied fauna. The island has two good harbors; Kilen to the west and Sommerstø to the east. On the northeast side of the island a seawall is built at a smaller inlet called Losholmen. This leds to two beautiful sandy beaches, one on each side of the pier. Tisler is worth checking out in good weather.
At most 30 people lived here. Today some year-round houses are preserved as vacation destinations. The entire shoreline and the adjacent islands and inlets are secured as a recreational area for the public, and all are part of the Ytre Hvaler National Park.
Tisler is an important nesting area for seabirds, and parts of the main island and surrounding islands are banned for visitors from 15 April to 15 July. Møren is one of the most important nesting sites for black-backed gulls in the Oslo Fjord.
st important nesting sites for lesser black-backed gull in the Oslo Fjord.