The reefs of the five islands making up the Bunaken-Manado Tua National Marine Park are reputed to be some of the best wall dives in the world. There are some 18 to 30 recognized dive sites around the islands.
Bunaken island is where you'll find most of the dive sites, as well as most of the dive resorts. Nearby Siladen has a couple of resorts as well.
All visitors to the park, whether they dive or not, must pay a one-time admission fee of 150,000 Rupiah (about US$15).