Halmahera

Halmahera is the largest island in the Maluku Islands, its interior covered in lush, largely intact rainforest and ringed by volcanoes rising directly from a calm sea. Most voyages depart from Ternate, the historic spice island off Halmahera's west coast, though some itineraries instead start in Sorong or Bitung near Manado. The region combines frontier-style reef diving with genuine World War Two history, including Japanese wrecks scattered through the surrounding waters, and is home to a species of walking shark found nowhere else on Earth. Trip length, exact route, and marine activities depend on the vessel and operator.

Marine biodiversity here is frequently compared to Raja Ampat's, and Halmahera shares similar geology and reef structure with its better-known neighbor, but at a markedly lower cost and with markedly fewer other visitors. The island's complex, convoluted coastline creates a wide range of habitats within a short sailing distance, from current-swept straits to sheltered bays good for macro photography. It remains, by most operators' own description, a frontier destination for divers seeking exploration and discovery rather than a settled, well-mapped circuit.

Halmahera's reefs benefit from the same biogeographic position that makes Raja Ampat so rich, sitting inside the same core of the Coral Triangle. The difference is visitor numbers: most sites here are dived only a handful of times a year.