Northwest of Manado, a 75-square-kilometre patch of sea is sectioned off as Bunaken Marine Reserve and promoted as Indonesia's official scuba centre, where coral reefs around the reserve's four major islands drop to a forty-metre shelf before falling into depths of 200m and more, creating stupendous reef walls abounding with Napoleon (maori) wrasse, barracuda, trevally, tuna, turtles, manta rays, whales and dolphin. Set aside concerns about snakes and sharks and avoid instead the metre-long Titan triggerfish, sharp-beaked and notoriously pugnacious when guarding its nest; and small, fluorescent-red anemone fish, which are prone to giving divers a painful nip.

You can visit the reserve in two ways, either on day-trips from Manado, which can be arranged privately or through dive operations, or by staying at budget accommodation within the reserve on Pulau Bunaken. If you need any training, qualified assistance or reasonable rental gear, opt for one of the pricier, professional dive operators in Manado itself. If you are already certified, have your own equipment and accept that you are not hiring a divemaster or instructor but only a dive guide of unknown competence, then save money by shopping around on Pulau Bunaken. In either case you must assume responsibility for checking out the reliability of rental gear and air quality , the two biggest causes for concern here. The best weather conditions are between June and November, with light breezes, calm seas and visibility underwater averaging 25m and peaking beyond 50m. Try to avoid the westerly storms between December and February and less severe, easterly winds from March until June.