Inner Oslo Fjord IslandsThe inner Oslo Fjord is known for its idyllic islands, which are a short ferry trip away from Oslo. Each island has its own distinct character, and everyone has a favorite. The largest and closest to Oslo, Hovedøya, has a beautiful forest and nature reserve for hiking and great beaches for swimming. Hovedøya is full of history, too: You can see the ruins of a 12th-century Cistercian monastery and two cannon batteries dating back to 1808. Lindøya Island is dotted with summer homes and Langøye Island is popular for camping and parties during the long summer days.