THE EXPEDITION

EXPERIENCE REQUIRED - ADVANCED OPEN WATER LEVEL WITH 50 DIVES MIN

Join Unique Ocean Expeditions for one of the most powerful and rarely witnessed underwater events on the planet, where the ocean doesn’t just come alive… it erupts with raw, untamed energy.

Each month, in the days leading up to the new moon, thousands of Bumphead Parrotfish (Bolbometopon muricatum) gather at specific channels to spawn. What begins as small groups builds rapidly into a dense, slow-moving mass of giants—fish weighing over 40kg—cruising against the current as the tension builds toward the main event.

This is not chance…….This is precision.

After years of exploration, hundreds of dives, and a deep understanding of moon phase, tide, and current flow, we’ve fine-tuned these expeditions to place you in the water at the exact moment when everything aligns.

We focus on one primary site—widely regarded as the largest aggregation of Bumphead Parrotfish on Earth. As the first light breaks on the horizon, we descend into position.

Then it begins.

From the blue, the school appears—hundreds… then nearly a thousand—stacking up in front of you. The energy builds slowly, almost eerily calm at first… before suddenly exploding into motion. The entire aggregation surges forward, bodies colliding, tails beating, releasing clouds of eggs and milt into the water column in a chaotic, synchronized rush.

You don’t just watch it……………You feel it.

This is nature at its most primal—raw power, scale, and intensity that very few divers will ever experience.

Over the course of the expedition, you’ll:

• Dive the primary aggregation site at the peak of the new moon cycle

• Experience multiple spawning dives in high-energy conditions

• Explore Palau’s world-class reefs, blue holes, corners, and iconic drift dives

• Gain real understanding through daily briefings and in-depth presentations

Expect early mornings, strong currents, and serious diving—this is for those who want more than just beautiful reefs.

All of our unique Palau itineraries are hosted by Palau Siren Liveaboard. With a liveaboard diving experience, you maximizing your time on the best sites when conditions are right.

Massive fish. Explosive action. Perfect timing.

This is Palau at its wildest…….Miss the moon… and you miss the moment.

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.

NEW MOON

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 nearly a thousand 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.

THE RATES

ALL CABINS ARE BASED ON SHARED OCCUPANCY

SPAWNING - 10 DAY ITINERARY - 8 CABINS - 16 Spaces - $6,440

ALL DATES

NEW MOON EXPEDITIONS PALAU SIREN LIVEABOARD

AVAILABLE DATES

ALL DATES ARE BASED AROUND MOON PHASES AND TIDES

PALAU LOCATION

PALAU SIREN ITINERARY

PRICE BREAKDOWN

EXCLUDES

• International & Domestic Flight

• Park Permits

• Gratuities

• Rental and Dive Gears

PALAU 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

Bumphead Parrotfish (Bolobometepon muricatum) Hidden on the West side of Palau lies a sandy slope perfect for the continuation of one of the oceans friendliest green giants. This is the biggest bumphead aggregation so far discovered on the planet. Most divers would be lucky to have witnessed a school of a hundred feeding around the reef, here you can see more than a thousand displaying color changes, males banging heads and a thousand fish spawning, truly a magical site.

Early in the morning  the school starts to form on the shallow reef top. One by one following each other from the shallows out onto the reef top like a waterfall, the aggregation begins to form. Hundreds turn into a thousand and the reef starts buzzing ready for a show.As a function of light and tide start to collide so do the bumpheads. Each green fish now starts displaying sexual dimorphism (colour changes). Bands and bars start appearing on the bodies and all heads are now white, the show is about to unfold.The huge school spills into the blue water and the fish begin schooling deeper and swimming at a faster rate . The mating dance begins, males and females swim backwards and forewords in some kind of untimely dance, white heads bobbing around in the deeper bluish water.You wait patiently for the first female to make her move, once this happens the whole school will rise and a mass spawn will happen in front of your eyes. Spawning for only a few intense minutes at first the school darts back into the deep and the mating dance continues, the females seeming to want to make the males work a little harder.Again another female breaks off from the huge school and rises closer to the surface, with eager males close behind. Again and again spawning rushes are happening all around you.This firework precision can last as long as thirty minutes or more in which time the school and spawning will slowly start to decrease as the tired bumpheads begin to leave the site.

A thousand soon dwindles down to less than a hundred and the once active site soon returns back to its original feeling as all the bumpheads begin to leave returning back  next month .   

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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