The Forgotten Islands

The Forgotten Islands — also known as the Southeast Moluccas — are a chain of volcanic and limestone islands stretching over 1,000 km from Timor to West Papua across the southern Maluku province. They earned their name because they sit between better-known destinations like Komodo and Raja Ampat, rarely appearing on mainstream travel itineraries despite containing some of Indonesia’s most pristine and least-dived reefs. The chain divides into two arcs: the Inner Banda Arc of active volcanic islands (Wetar, Romang, Nila, Damar) and the Outer Banda Arc of uplifted limestone islands (Leti, Luang, Tanimbar, Kei). Both arcs are reachable only by liveaboard — there is no resort infrastructure along the route.

The Forgotten Islands have two operating windows, both aligned with the inter-monsoon calm periods: April to May and October to November. These windows bring the calmest seas for the open-water crossings and coincide with the schooling hammerhead migrations at Serua, Nila, and Nils Desperandum. October to November is generally considered the more reliable window for large hammerhead schools and pelagic encounters. Outside these windows, rough conditions in the Banda Sea make the open-water transits between islands too uncomfortable and sometimes dangerous for standard liveaboard trips. Most boats run only one or two Forgotten Islands departures per year — availability is limited and fills well in advance.

The three main embarkation and disembarkation ports are Maumere (MOF) on Flores, Tual (LUV) in the Kei Islands, and Saumlaki (SXK) on Tanimbar island. All are reachable via connecting domestic flights from Jakarta or Bali through Makassar or Ambon — Wings Air (Lion Air Group) and Citilink operate most regional connections. Most trips run point-to-point, starting in one port and ending in another, so you need flexibility on both ends of your travel schedule. Your boat operator will confirm the embarkation and disembarkation ports and coordinate the airport transfer. Arriving the day before departure is essential given the multi-leg domestic connections involved.

The Forgotten Islands is one of Indonesia’s most demanding liveaboard destinations and is not suitable for newly certified divers. Most operators require a minimum of PADI Advanced Open Water certification plus 50–100 logged dives, with drift diving experience considered essential. The signature hammerhead sites at Serua and Nils Desperandum involve strong open-water currents, significant depths, and limited bail-out options. Some sites along the route — particularly around Nila and Wetar — may have been dived only a handful of times, meaning conditions are less predictable than at established sites. Comfortable buoyancy control, current reading ability, and experience diving in remote locations without nearby emergency services are all important before committing to this trip.

The Forgotten Islands deliver the full spectrum from large pelagics to dense macro. The headline encounters are schooling scalloped hammerheads at Serua, Nila, and Nils Desperandum — schools of 20 or more animals during peak season are not uncommon, making this one of the most reliable hammerhead destinations in the world outside the Galápagos. Oceanic mantas aggregate at Dullah Laut in the Kei Islands. Barracuda tornadoes at Manawoka are among the largest school formations in Indonesia. Bumphead parrotfish gather at dawn feeding aggregations in the Kei Islands. Reef sharks (blacktip, whitetip, grey), dogtooth tuna, giant trevally, and occasional whale sharks round out the pelagic picture. Macro life at Maumere includes ghost pipefish, frogfish, rhinopias, and blue-ringed octopus. Pilot whales, spinner dolphins, and orcas pass through the Banda Sea corridor seasonally.

Serua Island is the most celebrated hammerhead site on the route, with steep drop-offs and strong currents that concentrate sharks during peak season. Nils Desperandum is the remote southern seamount shared with the Banda Sea route — equally reliable for hammerheads and more remote still. Pulau Nila offers uncharted volcanic walls with visibility regularly exceeding 30 metres — some of these reefs have been dived only a handful of times. Manawoka delivers massive barracuda schools and frequent manta encounters. Dullah Laut in the Kei Islands is the most reliable oceanic manta site on the route. Kal’s Dream in Alor offers current-swept action with hammerheads in season. The Wairterang WWII wreck near Maumere makes an ideal first-day check-out dive.

The two destinations overlap in the southern Banda Sea — both include Nils Desperandum, Manuk, and Serua — but diverge significantly in character and logistics. The Banda Sea focuses on the historic Spice Islands, with cultural shore visits to Fort Belgica and nutmeg farms on Banda Neira as a central part of the experience. The Forgotten Islands push further east into the Southeast Moluccas, reaching the Kei Islands, Tanimbar, and Wetar — regions with almost no tourist infrastructure and even fewer visiting liveaboards. Trip lengths also differ: Banda Sea trips run 7–12 nights; Forgotten Islands trips typically run 12–16 nights. Many experienced divers choose to combine both on a single crossing itinerary of 14–18 nights.

Non-divers can join but should understand this is primarily a diving expedition. The remote character of the route means topside experiences are genuine rather than curated — volcanic peaks rising from the sea, traditional fishing villages that see almost no outside visitors, the Kei Islands’ extraordinary white-sand beaches, active volcanoes visible from the deck at night, and frigate bird colonies on uninhabited islands. Snorkeling at calmer sites along the route is possible, and some itineraries include shore visits to villages on the Inner Banda Arc. The long open-water transits between island groups mean there are stretches of a day or more at sea — non-divers should be comfortable with ocean passage and find the journey itself rewarding.

Most Forgotten Islands trips run 12 to 16 nights, reflecting the distances involved. A 12-night itinerary typically covers Maumere to Tual or Saumlaki, including Serua, Nila, and the Kei Islands but moving at pace. A 14 to 16-night trip allows more time at the best sites and the flexibility to wait for optimal tide conditions at the hammerhead seamounts — important given the distance traveled to reach them. Crossing trips that combine the Forgotten Islands with the Banda Sea extend to 16–18 nights. For a shorter western gateway option, Alor alone runs 7–10 nights from Maumere and covers the hammerhead and macro highlights without the full arc. The Forgotten Islands trip is not a destination for travellers who cannot commit to the time — the remoteness that makes it exceptional also means a shorter trip cannot cover the full arc.

Dullah Laut is a dive site in the Kei Islands at the eastern end of the Forgotten Islands route, known as one of the most reliable oceanic manta aggregation sites in Indonesia. Oceanic mantas are significantly larger than the reef mantas more commonly encountered elsewhere — wingspans of up to 7 metres are recorded. They aggregate at Dullah Laut during plankton-rich periods, particularly in the October–November and April–May windows that coincide with most Forgotten Islands itineraries. The Kei Islands reefs surrounding the site also host bumphead parrotfish feeding aggregations at dawn — one of the more dramatic reef fish spectacles in eastern Indonesia.

Above water, the Forgotten Islands route is as compelling as the diving. The Inner Banda Arc volcanoes — Damar’s 868-metre summit, Nila’s smoking craters, Wetar’s rugged interior — rise dramatically from flat sea. Komba volcano erupts every 20–30 minutes during active phases, with lava bursts clearly visible from the boat deck at night. Gunung Api hosts one of the largest frigate bird colonies in eastern Indonesia — dawn fly-pasts are extraordinary from the water. The Kei Islands at the eastern end have some of Indonesia’s finest white-sand beaches, accessible by tender between dives. Shore visits to tiny villages on the Inner Banda Arc offer rare glimpses of communities largely untouched by tourism, with traditional fishing practices and weaving techniques unchanged for generations.

Water temperature along the Forgotten Islands route ranges from 26–29°C year-round, with thermoclines dropping to 24°C or lower at depth during the inter-monsoon windows when cold upwellings are strongest — the same upwellings that drive the hammerhead aggregations. A 5mm wetsuit is recommended for the deeper drift dives at Serua and Nils Desperandum. A 3mm is adequate at shallower sites and calmer reef dives. Pack both. Beyond thermal protection, reef hooks are useful for the current-swept hammerhead sites, and a dive computer with a reliable gas integration is standard for this level of remote expedition diving. Spare parts for any critical equipment should be brought from home — there are no dive shops along the route.