THE EXPEDITION

EXPERIENCE REQUIRED - ADVANCED OPEN WATER LEVEL WITH 50 DIVES MIN

This is one of the rarest and most powerful spawning expeditions we offer—bringing together two of Palau’s most extraordinary natural events into a single, perfectly timed journey.

Only twice a year—March and April—the lunar cycles align to make this possible. Miss these windows, and the opportunity disappears.

Only a full immersion of a liveaboard on Palau Siren, with a schedule built around early morning dives and optional late-night sessions—can truely ensure you’re in the water exactly when the action peaks.

We begin with the explosive aggregation of the Blue-lined Sea Bream.

Over several days, you’ll witness what is believed to be the largest aggregation of this species ever discovered, with over 30,000 fish gathering in a dense, fast-moving mass. As the moment builds, the school tightens, surges, and erupts into a high-energy spawning event—an overwhelming wall of movement, scale, and intensity.

Then, just as that spectacle reaches its peak, we shift gears.

We transition into the raw, primal power of the Bumphead Parrotfish spawning event. Here, hundreds to over a thousand giant fish gather, moving with slow, deliberate force before bursting into action as they spawn—creating a completely different, yet equally unforgettable experience.

Two completely different rhythms.
One perfectly timed expedition.

To witness both of the largest known aggregations of these species on the planet in a single trip is something very few divers will ever experience.

Once the spawning events have concluded, we continue exploring the very best of Palau—diving manta ray cleaning stations, shark-filled channels, dramatic caverns, blue holes, swim-throughs, and even the surreal waters of marine lakes.

Massive schools. Giant fish. Perfect timing.

This is not just a dive trip—it’s a front-row seat to some of the greatest natural events in the ocean.

PALAU

Palau is widely regarded as one of the finest dive destinations on the planet—and for good reason. Its reefs are shaped by dramatic underwater topography, including sheer drop-offs, blue holes, caverns, caves, and fast-moving channels. Visibility is often exceptional, regularly reaching up to 100ft (30m), giving you that true “endless blue” feeling.

Wreck dives closer to Koror offer a different atmosphere, where visibility is typically reduced to around 15–45ft (5–15m)—but what they lack in clarity, they more than make up for in history and character.

Palau can be dived year-round, though the wetter season generally runs from July through October. Water temperatures are consistently warm, ranging between 81–86°F (27–30°C), making a 3mm wetsuit ideal for most conditions. That said, Palau likes to keep things interesting—seasonal thermoclines can drop temperatures into the mid-60s°F (23–26°C), especially on deeper dives.

Most sites are accessed via 45–60 minute speedboat rides from Koror, with the prime diving areas located around Ngemelis Islands and Peleliu—home to some of the most iconic dives in Micronesia. For this reason we choose a liveaboard experience to maximise our time on the ocean, offering four dives a day with early starts and late sunset dives.

Currents are a defining feature of diving in Palau. Driven by the Pacific Ocean, they create the conditions that make this destination so spectacular—but they also demand respect. Many sites are best suited for experienced divers, and a reef hook is essential, particularly on the outer reef walls like the legendary Blue Corner, where you’ll hook in and watch the ocean unfold in front of you.

For those with a passion for history, Palau also delivers. The waters around Koror are scattered with World War II wrecks, from cargo ships and transport vessels to navy destroyers and even Japanese Zero aircraft. Many are remarkably intact and easily accessible, offering a completely different—but equally compelling—side of Palau diving.

BLUE LINED SEA BREAM

In the days leading up to the new moon, the outer promontories of Palau begin to come alive. From across the reef, tens of thousands of Blue-lined Sea Bream (Symphorichthys spilurus) gather, drawn together by the precise pull of lunar phase and tidal flow.

What starts as scattered schools quickly builds into an immense, tightly packed aggregation—layer upon layer of fish stacking in the current as anticipation builds toward the main event.

We begin our expedition ahead of the new moon, diving Palau’s iconic current-swept sites as the conditions start to align. Each dive reveals more fish, more movement, more energy—until it’s clear something extraordinary is about to happen.

Then comes the moment.

Before sunrise, we head out. As the first light breaks across the horizon, we descend into the blue and take position.

From the depths, they rise.

A towering wall of sea bream surges upward, tightening into formation as the current pushes across the reef. Then suddenly—everything erupts. The entire aggregation explodes into motion, releasing clouds of eggs and milt into the water column in a synchronized burst of life.

It’s fast. It’s chaotic. It’s overwhelming.

An underwater firework display of scale and energy that few divers will ever witness.

And just as the action peaks, the predators arrive.

Bull sharks, oceanic blacktips, and reef sharks move in around the edges of the aggregation, drawn by the sheer density of life—adding another layer of intensity to an already electrifying scene.

Miss the timing… and you miss everything.
Get it right… and it’s something you’ll never forget.

BUMPHEAD PARROTFISH

In the days leading up to the new moon, something remarkable begins to take shape across Palau’s outer reefs and channels. From the lagoon and surrounding reef systems, hundreds—often thousands—of Bumphead Parrotfish (Bolbometopon muricatum) begin to gather, slowly building in numbers as they prepare for one of the ocean’s most extraordinary spawning events.

We start our expedition ahead of the new moon, diving Palau’s iconic current-swept sites as the anticipation builds. With each passing day, the signs become clearer—the fish are arriving, the energy is shifting, and the stage is being set.

Then comes the moment.

Before sunrise, we head out. As the first light breaks over the horizon, we descend into position and wait.

Out of the blue, they appear.

A steady procession of massive bumpheads begins to pour out of the lagoon, flowing onto the reef like a living river—building, layer by layer, into a powerful aggregation. What starts as a slow, deliberate movement quickly transforms into a surge of energy, as the entire group pushes forward to spawn, releasing clouds of life into the water column.

It’s not chaotic like other spawning events—it’s something different.

There’s a rhythm to it. A flow. A raw, majestic choreography that feels almost unreal to witness.

This is one of nature’s true spectacles—quietly powerful, deeply primal, and unforgettable.

Miss it… and you’d never know it happened……….Be there… and it stays with you forever.

PALAU SIREN - LIVEABOARD

LIVEABOARD EXPEDITION

ALL LIVE-ABOARD RATES ARE BASED ON PER PERSON.

THE RATES

PALAU SIREN

ALL CABINS ARE BASED ON SHARED OCCUPANCY

SPAWNING - 10 DAY ITINERARY - 8 CABINS - 16 Spaces - $6,640

ALL DATES

NEW MOON SEABREAM & BUMPHEAD COMBO EXPEDITIONS

PALAU SIREN LIVEABOARD

2027 DATES

2028 DATES

2029 DATES

PRICE BREAKDOWNS

EXCLUDES

• International & Domestic Flight

• Park Permits

• Gratuities

• Rental and Dive Gears

DIVE INFORMATION

WATER TEMPERATURE - 27c / 85F

WETSUIT - 3mm / 5mm

• Blue Corner, one of Palau's most magical dives, is known for its sheer abundance of underwater life and reef configuration – the corner sticks out into the open ocean and then drops to the depths. Divers are dazzled by the incredible variety of fish, including barracudas, jacks, Napoleon wrasses and schooling grey reef sharks. Strong tidal currents render it a dive for the more experienced – a reef hook is a must to remain stationary in the current.

• Blue Holes, may well be Palau's most scenic dive. It features four vertical shafts that open on the top of the reef and descend to a large cavern that exits on the outer wall at about 25m. Drifting down the shafts is a delight, especially when the sun is high. Dancing rays of sunlight flood through these openings and play with the blue hues. Schools of fish patrol the huge bottom exit, with dark blue ambient light as a background.

• German Channel, Given the right set of circumstances, a dive at German Channel can be an unforgettable experience. Manta rays regularly visit this channel, which was blasted by the Germans to ease boat passage during their 1899 to 1914 Palau occupation. The mouth of the channel features some nice sandy areas with small cleaning stations, where mantas (usually two to five individuals) come to have parasites removed by little cleaner wrasses in less than 20m of water.

• Peleliu Island, If you'd like to temporarily escape the relative hustle and bustle of the capital, the small coral island of Peleliu, in the south of the archipelago, offers a tranquil option. There's only one village – Klouklubed – and often it will seem like you've got the entire island all to yourself. The diving here is concentrated around the south East tip of the Island. Deep walls, strong currents and an abundance of fish life make this one of Palaus best dive locations.

• Ulong Channel, is one of most thrilling dives in Palau. Divers start at the mouth of the channel, which consistently sizzles with fish action. Divers usually hook themselves to the reef to see hunting grey and whitetip sharks, jacks, barracudas and groupers, before drifting with the current along the channel. The seascape is incredibly scenic: the sea floor is carved by large parallel-running white-sand valleys, bounded by healthy coral formations and dotted with massive sections of sprawling lettuce corals.

• Siaes Corner, When the tide is running and the month is right you can see more than 300 grey reef sharks here. Siaes Corner is a current-swept point that plunges vertically to about 50m. After jumping in the water, divers drift along the wall to the corner. As you reach the corner, you attach your hook to a dead coral to watch for electric fish action, which usually includes grey sharks, blackbar barracudas, jacks, bumphead parrotfish, anthias and fusiliers.

• Shark City, is the outer most promentory in Ulong and sometimes one of the best dives in Palau. Conditions are similar to Peleliu with strong current and action dives along with high rewards such as bull sharks, oceanic blacktips and pelagic encounters. The corals and reef life is also spectacular.

SPAWNING DIVE INFORMATION

EARLY MORNING STARTS

POTENTIAL CURRENT DIVES

The Blue Lined Sea Bream (Symphorichthys spilurus) can be seen during the months of March, April and sometimes May. These strange but beautiful looking fish form one of Palau’s largest recorded spawning aggregations to date. A rarely seen fish on the reef these normally solitary fish hide inside the lagoon or on deep sandy drop off’s, feeding on crustaceans hidden in the sand and normally away from the eyes of divers.

As their spawning season approaches individuals start gathering in two main areas of Palau. One in the North West side called Tailtop and one in the South, around the island of Peleliu. This aggregation can reach up to 50,000 fish and just seeing the size of the school when its together can be more impressive than the actual spawning event itself. When the correct formula of month, day, tide and time come together the Sea Bream are ready to spawn.

The school moves from its aggregation area to an area with current, taking their gametes to safety. From 60m to 15m the school becomes a tight mass of yellow fusion and the fish begin spawning. Bullsharks (Carcharhinus leucas), Blacktip sharks (Carcharhinus limbatas) and often lemon sharks (Negaprion brevirostris) are seen slowly swimming through the school waiting for a tired fish to pick off.

PRESENTATIONS

During your stay with us your Expedition Leader and Location Expert will be working together delivering you in depth presentations regarding the biology of what we are witnessing. These presentations have taken years to formulate and develop and what makes part of our collaboration with Unique Dive Expeditions so special.

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