The main beach on Biak's eastern coast, about 15 km from the town centre by road, Bosnik is a long stretch of white sand facing the calm waters of Cenderawasih Bay. The bay is sheltered from the open Pacific swells, which makes the water consistently calm and the snorkelling directly off the beach productive — the reef begins close to shore and the visibility is typically excellent.
Bosnik is the closest beach to town and the most accessible for a half-day trip. Local boats can be chartered from the beach to reach offshore dive sites and the islands of the inner bay. Weekend afternoons see Biakanese families using the beach; on weekday mornings you may have long stretches of it to yourself. There are small warungs (food stalls) selling fresh fish, rice, and cold drinks. Bring reef shoes — the shallow section near shore has some coral rubble.