5-Day Derawan Islands Diving Itinerary: Turtles, Manta Rays & Jellyfish Lake
Off the coast of East Kalimantan, the Derawan Archipelago is one of the few places on Earth where you can dive alongside green turtles on nearly every reef, watch manta rays circle a cleaning station, and swim through a landlocked lake filled with jellyfish that have lost their sting. Despite sitting inside the Coral Triangle — the same waters that feed Raja Ampat's biodiversity — Derawan remains far quieter than Bali or Komodo, which is exactly why it keeps showing up on 2026 "next big thing" lists for Indonesia. This itinerary covers five days across the archipelago's four main islands: Derawan, Sangalaki, Kakaban, and Maratua.
Why Derawan, and why now
Derawan isn't a single island but a scattered archipelago in the Berau Regency, administered from the mainland town of Tanjung Redeb. Four islands do most of the work: Derawan itself is the transport hub and the easiest to reach; Sangalaki is a protected turtle-nesting beach and a reliable spot for manta ray encounters; Kakaban holds a prehistoric marine lake cut off from the ocean for thousands of years, where jellyfish evolved without predators and lost their ability to sting; and Maratua is the largest island, ringed by a barrier reef and increasingly the base for serious divers thanks to a handful of dive resorts on stilts over the lagoon.
What makes the region worth five full days rather than a weekend stopover is that each island specializes in something different. You are not repeating the same reef with a different sunset — you are moving between four distinct ecosystems within a two-hour boat ride of each other.
Getting there
The gateway is Kalimarau Airport (BEJ) in Tanjung Redeb, Berau, reachable via a roughly 1-hour connecting flight from Balikpapan (which itself has frequent connections from Jakarta, Surabaya, and other major cities). From Tanjung Redeb, most travelers take a road transfer of about two hours to the port town of Tanjung Batu, followed by a 30–45 minute speedboat crossing to Derawan Island. Some resorts on Maratua now also offer direct speedboat transfers from Tanjung Batu, cutting out an island-hopping leg.
A faster but pricier alternative is flying into Maratua's small airstrip when seasonal flights are operating, which trims the transfer time to under an hour from Tanjung Redeb. Because schedules shift year to year, it's worth confirming current routes with your accommodation before booking onward flights.
Best time to visit
Derawan is diveable year-round, but the calmest seas and best visibility typically fall between April and October, outside the peak of the west monsoon. Manta ray sightings at Sangalaki are most consistent from April through August, when plankton blooms draw them to the cleaning stations. If turtle nesting is the priority, Sangalaki sees activity throughout the year, with a noticeable peak from July to September.
Day 1: Arrival and Derawan Island
After the flight-and-boat journey in, spend the afternoon settling into Derawan Island itself. This is the most developed of the four islands, with guesthouses, dive shops, and a jetty where green turtles are famously visible without even entering the water — they surface for air metres from the pier, especially around dusk. Take an easy check-out dive or snorkel session on the house reef to shake off travel fatigue, then walk the island's ring road (it takes under an hour) to get oriented.
In the evening, most dive operators will brief you on the coming days and check certification levels — Open Water is the minimum for most sites, though several dives are shallow enough for confident snorkelers to enjoy the surface action while divers go deeper.
Day 2: Sangalaki — manta rays and turtle beaches
Sangalaki is a short boat ride from Derawan and built around two things: a resident population of reef manta rays that gather at cleaning stations just offshore, and a beach that is one of Southeast Asia's most important green turtle nesting sites. Morning dives here typically target the cleaning stations, where mantas glide in slow circles while cleaner wrasse pick parasites off their skin — a dive that regularly runs long because nobody wants to surface.
In the afternoon, join a ranger-led beach walk (research stations on the island track nesting activity) to learn about the conservation work protecting the population, then take a second dive or snorkel along the fringing reef, which is shallower and calmer than Maratua's outer walls.
Day 3: Kakaban — the stingless jellyfish lake
Kakaban is unlike anywhere else most divers will ever visit. A tectonic uplift sealed a lagoon off from the surrounding sea thousands of years ago; over time, the jellyfish trapped inside evolved in the absence of predators and lost most of their ability to sting, since they no longer needed to defend themselves. Today Kakaban Lake is one of only two such lakes on the planet (the other is in Palau), and swimming or snorkeling through clouds of golden and moon jellyfish that drift past without stinging is the single most-photographed experience in the archipelago.
A short, sometimes slippery boardwalk climb over limestone cliffs gets you from the boat landing to the lake itself — sturdy sandals help. Diving is not permitted in the lake (snorkeling only, to protect the fragile ecosystem), but the reef wall just offshore from Kakaban is one of the best wall dives in the region, dropping into deep blue with strong currents that attract larger pelagic fish.
Spend the rest of the day back on Maratua, where you'll base yourself for the final stretch.
Day 4: Maratua — Big Fish Country and the blue lagoon
Maratua is the biggest island in the group and home to the archipelago's most serious dive sites. "Big Fish Country" and Nabucco Point are the standouts: expect schooling barracuda, jacks, and reef sharks patrolling a wall that drops into the deep, with currents strong enough that most operators run these as drift dives. Turtle Traffic Jam, true to its name, is a shallower site where it's common to have a dozen turtles in view at once.
Between dives, Maratua's inner lagoon — a turquoise, mostly enclosed bay ringed by the island's arc — is worth an afternoon on its own. Kayak or paddleboard across it, or simply swim; the water is calm and warm enough to spend hours in without a wetsuit. If you're not diving, this is also a good day to arrange a village visit to see the stilt houses of the Bajau community, some of Southeast Asia's most skilled traditional free-divers.
Day 5: Departure
Plan a morning dive or snorkel if your flight schedule allows — many visitors save a final easy reef dive near the resort for their last morning rather than rushing straight to the boat. Budget at least three to four hours for the return transfer to Tanjung Redeb (boat plus road) if you're catching a flight out of Kalimarau Airport the same day, and build in extra buffer during rainy season when sea conditions can slow the crossing.
Budget breakdown
Derawan is not a backpacker-cheap destination, mostly because of the boat transfers and marine park fees, but it remains significantly less expensive than Raja Ampat for a comparable diving standard.
- Marine park entry fee: a per-visit conservation fee applies on Sangalaki, Kakaban, and Maratua, generally in the range of Rp 100,000–200,000 depending on the island and whether you're diving or snorkeling.
- Accommodation: simple guesthouses on Derawan Island run from around Rp 300,000–500,000 per night; dive resorts on Maratua with full board and dive packages range from roughly Rp 1,000,000–3,000,000+ per night depending on comfort level.
- Diving: a two-tank dive day with a local operator typically costs Rp 800,000–1,500,000, with multi-day packages offering a discount per dive.
- Transfers: the Tanjung Batu speedboat crossing runs Rp 150,000–300,000 per person depending on whether you join a shared or chartered boat; inter-island boat hops during the trip add up to a similar amount per day.
A five-day trip with mid-range accommodation and two dives a day typically lands somewhere between Rp 6,000,000 and Rp 12,000,000 per person, excluding international or domestic flights to Balikpapan.
Practical tips
- Book dive operators in advance: Derawan's dive infrastructure is smaller than Bali's, and boats fill up around peak manta and turtle nesting season (June–September).
- Bring cash: ATMs are unreliable to nonexistent on the smaller islands; withdraw what you need in Tanjung Redeb or Balikpapan before heading out.
- Reef-safe sunscreen only: given the marine park status of Sangalaki and Kakaban, mineral sunscreens are strongly preferred and sometimes checked.
- Connectivity is limited: expect patchy signal on Derawan and very little on Sangalaki, Kakaban, or the outer parts of Maratua — treat this as a genuine digital-detox stretch.
- Pack for the boat transfers: dry bags for cameras and electronics are worth the extra weight, since open-boat crossings can mean spray even on calm days.
Who this itinerary suits
This five-day plan is built around a moderate diving pace — two dives most days, with time built in for the Kakaban boardwalk and a lagoon afternoon — rather than a tech-diving or dive-course-heavy schedule. Snorkelers can follow the exact same route; every site on Derawan, Sangalaki, and the Maratua lagoon has shallow, calm sections, and Kakaban Lake is snorkel-only regardless of certification. Families with older children and confident swimmers manage it comfortably, though the open-boat transfers are worth factoring in if anyone is prone to seasickness.
If you'd rather not island-hop between separate guesthouses, basing yourself on Maratua for nights two through four and day-tripping to Sangalaki and Kakaban is the easiest way to run this itinerary without repacking every morning.
Frequently asked questions
Do I need a diving certification to visit? No. Snorkeling covers most of the marine highlights, including the Kakaban jellyfish lake, the Derawan turtle jetty, and the shallow edges of Sangalaki's reef. A certification opens up the deeper wall dives at Maratua.
Is Derawan crowded? Not yet, especially compared with Bali or Komodo. Boats and dive slots do tighten up in the June–September peak season, so book ahead rather than arriving without reservations.
Can I do this trip on a budget? Yes, though it takes more planning than backpacking Bali — shared boats, guesthouse stays on Derawan Island, and self-guided snorkeling instead of resort dive packages bring the daily cost down considerably.
Five days is enough to see all four islands without feeling rushed, but divers chasing certification courses or wanting extra time with the mantas at Sangalaki should budget a sixth or seventh day. Either way, the Derawan Islands deliver an unusually concentrated stretch of marine encounters — turtles, mantas, sharks, and a one-of-a-kind jellyfish lake — in a corner of Indonesia that, for now, still feels genuinely uncrowded.