Mosterhamn or simply Moster is a village in Bømlo municipality in Vestland county, Norway. The village is located on the small island of Moster in the southeastern part of the municipality of Bømlo. The village lies along the Bømlafjorden. The 1.8-square-kilometre (440-acre) village has a population (2019) of 1,375 and a population density of 764 inhabitants per square kilometre (1,980/sq mi).