Blomøyna or Blomøy is an island in Øygarden municipality in Hordaland county, Norway. The island is the second largest island in the municipality. The island lies north of the island of Rongøyna and south of the island of Ona. The southern part of the island is split into two parts by the Blomvågen fjord which cuts northward for into the island. The village of Blomvåg surrounds the inner part of the Blomvågen fjord. Nearly all of the island's residents live in Blomvåg. Blomvåg Church is located in the village, serving the whole southern part of the municipality.