The current at the mouth of the Channel arrives without warning. One moment you're drifting lazily over the reef; the next, an invisible hand is pulling you along, and out of the blue haze ahead a wall of silver appears—first a handful of barracuda, then dozens, wheeling together in a slow-motion vortex. Off to one side, a whitetip reef shark glides past unbothered. A green turtle keeps chewing on soft coral, indifferent to the bubbles a few feet away. Every so often the shadow of a passing manta ray blots out the surface light. This is Big Fish Country, one of the fishiest single dive sites anywhere in Indonesian waters—and there's a decent chance you'll have it shared with only one or two other boats, if that.
That contrast is exactly why Maratua Island, in Berau Regency, East Kalimantan, keeps coming up in dive forums as Borneo's answer to Raja Ampat or Bunaken: world-class marine biodiversity without the boat queues, multi-story resorts, or a reef shared with a hundred other snorkelers. For years Maratua stayed mostly on the radar of hardcore divers chasing the next frontier. That's starting to change. Air connectivity into North and East Kalimantan is quietly improving—Tarakan's Juwata Airport had its international status reinstated by a Transportation Ministry decree in August 2025, and carriers are now in talks to open new routes, including to China and Malaysia—putting this horseshoe-shaped atoll on more travelers' radar than ever. If there's a moment to visit before Maratua starts looking like its more famous cousins further east, this is probably it.
Where Maratua Actually Sits
Maratua is one of four principal islands in the Derawan Archipelago, a scatter of roughly 31 islands in the Celebes Sea off the eastern coast of Kalimantan, administratively part of Berau Regency. Its three siblings each have their own claim to fame: Derawan Island, the easiest to reach and the archipelago's logistical hub; Sangalaki, known for its manta rays; and Kakaban, home to a lake of stingless jellyfish found almost nowhere else on Earth. Unlike flat, sandy Derawan, Maratua is an ancient coral atoll shaped like a horseshoe—a fossil reef that rose out of the sea, enclosing a turquoise lagoon and ringed by steep outer walls dropping into deep water. That geology is why the water runs so clear: far from any major landmass and its river sediment, visibility at the best sites regularly reaches 20 to 40 meters, with some accounts putting it as high as 60 meters in ideal conditions.
The Story Underwater: Turtles, Sharks, and Mantas
Maratua's reputation among divers rests on more than 20 named dive sites ringing the atoll, each with a distinct personality. The Channel, also called Big Fish Country, is the headline act already described above: a current-swept passage that funnels food and, with it, schools of barracuda that some operators consider among the largest in Southeast Asia, plus whitetip sharks, giant trevally, and the occasional hammerhead. Not far away is Turtle Traffic, a site whose name says it all—green and hawksbill turtles cruise so calmly around divers that an encounter on nearly every single dive is close to guaranteed. That's not a coincidence: Maratua is recognized as an internationally significant green turtle nesting site, and conservation groups like the Turtle Foundation work directly with island communities to protect nests along its beaches from egg poaching and other threats.
For divers who prefer the small stuff, the Jetty site near the main pier hides a surprising amount of macro life—mandarinfish that come out to dance at dusk, harlequin shrimp, blue-ringed octopus, and tiny crustaceans tucked into every crevice. Eel Garden, with stronger current and greater depth, holds a dense population of garden eels and is best left to experienced divers. At the other end of the spectrum, Cabbage Garden (sometimes called Cabbage Patch) is a sheltered, nearly current-free lagoon carpeted in overlapping cabbage coral, ideal for beginners or an easy snorkel. Add Hanging Garden, where eagle rays and two separate barracuda schools often appear together, and all-purpose Mid Reef, and Maratua packs a genuinely wide range of diving into a tight radius—from adrenaline drift-walls to calm lagoons where you're still learning to clear a mask.
Kakaban: A Jellyfish Lake Almost Unlike Anything Else on the Planet
While you're based on Maratua, don't skip the short crossing—about 15 to 20 minutes by speedboat—to Kakaban Island. At its center sits an ancient brackish lake, formed more than 11,000 years ago when a section of reef was pushed above sea level and its trapped seawater gradually turned brackish, sealed off from the open ocean. Over that long geological stretch, the jellyfish trapped inside evolved to lose their sting entirely, having no natural predators left to defend against. The result is a lake filled with thousands of golden jellyfish that visitors can swim and snorkel among safely—a phenomenon that, as far as science currently knows, exists in only two places on the planet: Kakaban and Jellyfish Lake in Palau, Micronesia.
Because the ecosystem is both unique and fragile, the rules are strict: no scuba gear, only surface swimming or snorkeling; no sunscreen before entering; and visitors are asked to kick gently so as not to disturb the lakebed sediment the whole ecosystem depends on. Kakaban's jellyfish population has come under real pressure from visitor surges in the past, and management has since tightened—one more reason to go relatively soon, while numbers here stay well short of what Palau's version has weathered at its own peak.
Derawan and Sangalaki: The Rest of the Archipelago
Because nearly every boat route to Maratua stops first at Derawan Island, it's worth budgeting time there too. Livelier and more developed than quiet, sparsely populated Maratua, Derawan functions as the archipelago's logistical hub—more guesthouses, more places to eat, and a wooden jetty that's become one of Indonesia's most iconic snorkel spots in its own right, since green turtles swim close enough to its pilings to watch from a shallow snorkel without ever needing a tank. Sangalaki, roughly 45 minutes to an hour and a half away by speedboat from Maratua depending on the operator and sea state, hosts a reliable manta ray cleaning station—one of the more dependable places in Indonesia to snorkel or dive alongside mantas without waiting days for a single sighting.
How to Actually Get There
This is the part that scares off would-be visitors, though the routing is more straightforward than it looks. From Jakarta or Bali, the most direct gateway is Kalimarau Airport (BEJ) in Tanjung Redeb, Berau's capital—Batik Air runs a direct Jakarta–Berau route, while travelers from other cities typically connect through Balikpapan, which has several daily flights to Berau on carriers like AirAsia, Super Air Jet, and Wings Air. An alternative is routing through Juwata Airport in Tarakan, whose importance as a North Kalimantan gateway is growing as its international status is reactivated and new routes are explored.
From Berau, it's roughly a two-hour overland transfer to Tanjung Batu port, then a chartered or public speedboat out to the Derawan Islands—usually with a stop at Derawan before continuing on to Maratua, total boat time running two to three hours depending on the sea and departure point. Most dive resorts and homestays on Maratua offer airport-to-island transfer packages, far less of a headache than piecing the journey together leg by leg.
A Realistic Multi-Day Itinerary
Give this trip at least four to five days so it doesn't feel rushed. The first day is usually consumed by transit—airport to port, then the boat crossing to the islands. The next two or three days can center on diving around Maratua: The Channel when the current cooperates, an easy session at Turtle Traffic, and a calmer macro dive at Cabbage Garden or the Jetty. Set aside one full day for island-hopping: a morning snorkel with mantas at Sangalaki, an afternoon crossing to Kakaban to swim with the jellyfish, and, time permitting, a final stop at Derawan itself before heading back toward Berau or Tarakan.
What to Know Before You Go
Maratua's diving season runs broadly from March through December, with the best combination of weather, visibility, and marine life activity generally falling in the dry season, July through October. Manta sightings, on the other hand, are more consistent over a longer window, from October through June, so it's worth picking your dates based on what you're chasing—big current and pelagics, or reliable manta encounters. Water temperature stays warm year-round, around 28 to 30°C, so a thin wetsuit is usually all you need.
Accommodation is genuinely limited, and that scarcity is part of the appeal: options on Maratua are mostly small dive resorts and family-run homestays rather than resort chains. Limited room counts mean booking well ahead in peak season, and adjusting expectations—electricity and internet at some homestays still run on generators and patchy signal. Bring enough cash, since ATMs are essentially nonexistent here, along with personal medication and reef-safe sunscreen, given the nearest pharmacy is back in Tanjung Redeb.
For divers, a basic Open Water certification is enough for most of the calmer sites, like Cabbage Garden or the Jetty, but current-swept spots like The Channel and Eel Garden are better approached with advanced experience, or at minimum a dive guide who knows how the currents behave—conditions here can shift strong within minutes as the tide turns. If you're not certified yet, nearly every dive center on Maratua and Derawan runs introductory dives or full Open Water courses on-site, so there's no need to put off the trip just because you've never strapped on a tank.
Why Go Now
The Derawan Archipelago, with Maratua as its diving heart, has every ingredient that usually turns a destination into a phenomenon: iconic marine species, extraordinary underwater visibility, and a genuine conservation story running through active turtle-nest monitoring and the careful management of Kakaban's jellyfish lake. What it doesn't yet have—at least for now—is the crowding that usually arrives alongside that kind of fame. Slowly improving air access into Berau and Tarakan suggests that window won't stay open indefinitely. For anyone tired of sharing a reef with dozens of snorkel boats at destinations that got famous first, Maratua still offers something increasingly rare: water that feels like it's yours alone.