Indonesia — Raja Ampat
Raf's Reef Brief
West Waigeo
Visited December 18-21st, 2025
Written August 21st, 2026
'West Waigeo' is our term for the extensive fringing reefs & mangrove forests on and in the islands around southwest Pulau Waigeo. The largest of the 'four kings' islands from which Raja Ampat derives its name, Waigeo has an area of about 3100 kilometers—so this brief will narrow its focus to the area bounded by Pulau Gemien above & Pulau Gam below. Adjacent to the Dampier Strait's powerful warm ocean current, this region's limestone islands, bays, and channels create a complex web of water exchange. This, alongside a general lack of sediment-heavy rivers & mud flats, results in an unusually clear terrestrial coastline regularly flushed by nutrient-rich flows.
This combination of geology, oceanography, and ecology is responsible for the uncommon & dramatic intersection of mangrove forest and coral reef environments that can be found throughout greater Raja Ampat, and West Waigeo is no exception. Here we can find traditional patch & fringing reefs dominated by branching Acropora hard corals, only a stone's throw away from mangrove roots decorated in soft corals perched above beds of the fragile hard coral genus Seriatopora.
Branching Acropora thrives in a diverse array of colors & species on the sheltered reefs around West Waigeo
While the upper portion of this location is uninhabited when compared to the rest of Raja Ampat, the corals here haven't been spared from devastation. Loads of fishing boats fish West Waigeo while hoards of daytrips & liveaboards arrive every day to see several famous sites in the south half of the area. Particularly the mangrove channels near Kabui & Yanggelo and the karst islands around Pef. Consequently, there is active development to increase the already large number of homestays on northern Gam.
Like in the Fam Islands, it is evident that this volume of tourism & exploitation is unsustainable for the local hard coral cover, as many sites contained active mortality driven by either nutrient indicators or Crown of Thorns Starfish (COTS). These issues are most likely due to high concentrations of human sewage in the water, released locally by the aforementioned liveaboards & homestays, as well as the overfishing of keystone predators. These issues are known drivers of COTS outbreaks and nutrient loading, which greatly increase hard coral mortality & susceptibility to climate change.
A slope of Montipora & Anacropora suffers one of many moderate COTS outbreaks in the region, evidenced by the many stark white skeletons & collapsing colonies
While I was initially horrified by the number of COTS outbreaks across the region and the scrappy condition of the most famous mangrove sites (yeah, I'm talking about you, Citrus Ridge), the respectable amount of high cover reefs & mangrove coastline we found during explorative snorkels made this a location to remember. This was especially true after visiting the actively degrading Fam Islands and hit-or-miss North Raja, two locations that had left me disappointed only days prior.
I would recommend West Waigeo's hard corals for diving/snorkeling and conservation/research, but only once liveaboard traffic and homestay sewage output is regulated across this region, particularly in Gam. Even the high cover exploatory sites presented here will degrade if we don't relieve nutrient loading pressures.
Walkthroughs of Western Waigeo
Surveying the reefs of West Waigeo was a significant challenge logistically & physically. There are very few accommodations in the north of the region and most of the myriad of homestays on the southern coast of Gam do not support scuba diving. Additionally, high local fuel costs, storms, strong currents, freshwater shortages, and a lack of continuous power here are equally as troublesome as elsewhere in Raja Ampat. But worst of all is the risk of encounters with saltwater crocodiles, something which West Waigeo is infamous for. This should be unsurprising given the number of terrestrial & mangrove habitats in the area, though that didn't stop me from being any less scared.
Nonetheless, we reviewed 11 sites from December 18th to 21st for hard coral health, whose walkthroughs and data can be viewed below. Some sites may have their names, coordinates, and maps censored if the corals are deemed too vulnerable to be shared with the public.
Sites Table of Contents
Site One
December 18
A bommie coated in young plating Acropora sprouts out of a sea of other Acroporidae species
Site One consists of an east-to-west fringing reef that ends with a large 'triangular' plateau. The rest of the reef is made up of a sloping upper fore reef adorned with a shallow reef flat that gives way to a sandy slope at ~7m deep. The coral cover waxes and wanes & is dominated by a mix of Acroporids and massive Porites. Nutrient indicators were present and there was a moderate COTS outbreak of 20+ adult individuals. Currents were strong to moderate & visibility ranged from poor to high.
Frankly, I was quite pleased by this reef by the end of the day. The COTS outbreak was indeed horrifying as were the scrappy sections of cover & disease, but man if that Acropora cover at the end wasn't nice! For an exploratory site in a seldom visited area, it was a good start to our time in West Waigeo.
Site One Site Walkthrough
Site One Reef Site Data
Mangrove Reef
December 19
Green Isopora brueggemanni, a species adapted for exposed high-flow environments, uncharacteristically grows beneath mangrove roots
Mangrove Reef is a named site on the southwest side of the popular channel between Pulau Yanggelo and the mainland of Gam, consisting of both an exposed reef flat followed by a thin sheltered fringing reef beneath stands of mangroves. Coral cover is diverse but varies in health and density throughout the site. There was a small COTS outbreak and significant amounts of disease and cyanobacteria. This site is one of three in this channel that are visited almost every day by multiple liveaboards & daytrips, and there are two homestays in the channel itself. Currents started very strong but were mild inside the channel and visibility started high but was generally moderate.
Looking back at this site, I'm not really impressed. While I enjoyed the coral cover here initially, both the exposed reef and mangrove area were unhealthier than the same environments in other exploratory areas of West Waigeo. The same can be said for the other two sites that we visited in this channel, but I'll save that for later.
Mangrove Reef Site Walkthrough
Mangrove Reef Site Data
Yanggelo Southwest
December 19
The columnar Isopora palifera dominates the exposed fringing reef at Yanggelo Southwest
The exposed fringing reef on the southwest side of Pulau Yanggelo consists of an east-to-west wide shallow terrace above a slope with a bay at one side and a deeper corner-like plateau at the other. The site is dominated by dense branching Acropora & columnar Isopora palifera, though a majority of the site is either bare, sandy, destabilized, or actively suffering from a moderate COTS outbreak. Currents ranged from non-existent to strong and visibility was moderate.
We added this exploratory site to our day trip to the famous Yanggelo/channel area on behalf of a request to examine the aftermath of a past COTS outbreak. As a result, we couldn't spend very long here, which didn't end up bothering me given the site is so degraded. A testament to the danger that COTS outbreaks pose to coral reefs!
Yanggelo Southwest Site Walkthrough
Yanggelo Southwest Site Data
Site Four
December 19
A plating Acropora grows above a carpet of Seriatopora hystrix, a fragile species that is suited for the calm sheltered waters at Site Four
Located along a limestone cliff & mangrove coastline in a popular high flow channel, Site Four is a protected fringing reef with a shallow reef flat above a gradual sandy slope. The site is largely dominated by Seriatopora hystrix with small sections of branching Acropora. There is active human development and an open bottom septic tank nearby. Consequently, there is a significant amount of disease, cyanobacteria, and mechanical damage which has led to some large ruts. Currents were mild to non-existent and visibility was always high.
Despite the nutrient indicators present (which indeed made me sad), this was the only site in the famous channel area that seriously impressed me in continuous coral cover. A large bed of more-or-less live & intact Seriatopora is not to be missed! The fish life didn't hurt either.
Site Four Site Walkthrough
Site Four Site Data
Citrus Ridge
December 19
Colonies of Acropora & various soft corals alike thrive in the high flow channel above Citrus Ridge
The famous Citrus Ridge is the portion of fringing reef that makes up the northwest corner of the popular channel between Pulau Yanggelo & Gam. The site is near two homestays and is visited several times per day by divers and snorkelers. The upper fore reef and reef flat are largely defined by soft corals, though there are some hard corals present. There is also a deep 'T'-shaped ridge ~20m deep dominated by non-photosynthetic soft corals parallel with the fringing reef, where divers usually go. Currents were usually very strong and visibility was always high.
Despite its hyped reputation, Citrus Ridge didn't impress me. The soft coral environment (whether natural or an outcome after hard coral death) isn't our focus nor were we able to dive the area to see its most famous part, the deep ridge. An underwhelming end to our day on the popular channel.
Citrus Ridge Site Walkthrough
Citrus Ridge Site Data
Site Six
December 20
Fast growing table Acropora can quickly overshadow surrounding competitors
Site Six is a fringing reef that wraps around the corner of an island, which forms a large reef flat with multiple sides. The southern side is an exposed, sloping fore reef dominated by scrappy, beat up Isopora palifera. The perpendicular side of the reef is more of a protected reef flat over a very steep slope. This side is higher in cover, dominated by Acropora & Montipora. There are significant nutrient indicators and a small COTS outbreak across the site. Currents ranged from moderate to very strong & visibility was generally high.
While the initial bombed-out start of Site Six was depressing, the higher cover towards the middle and end made it worth it. Not bad for an exploratory site that is rarely visited! A large school of bumphead parrotfish was the icing on the cake.
Site Six Site Walkthrough
Site Six Site Data
Site Seven
December 20
The endless field of branching & tabling Acropora at Site Seven
Site Seven is a large section of exposed fringing reef consisting of a wide sandy upper fore reef, shallow bare reef crest, and an extensive back reef. The coral cover is generally low except for two areas of back reef where extensive fields of dense Acropora cover can be found. Some nutrient indicators and mild bleaching were present. Currents started very strong but ended non-existent and visibility ranged from high to low.
Personally, I really enjoyed this reef. Even though much of the site was either damaged or bare, the two Acropora matrices were a site to behold. I just wish I didn't have to survive getting over the long-gone reef crest while waves broke over my head to reach them—whatever, worth it!
Site Seven Site Walkthrough
Site Seven Site Data
Site Eight
December 20
A diverse section of the upper fore reef at Site Eight, with six genera of hard corals present in one photo!
Site Eight is a long semi-exposed fringing reef on a limestone island consisting of a wide reef flat and a gently sloping upper fore reef that gives way to a steep sandy slope below. Hard coral cover on the reef flat and upper fore reef was very high and healthy, with only a few exceptions. Corals of the family Acroporidae were always dominant but high diversity was present across the site. There were very few negative indicators here at all, though a few COTS, disease, and other stressors were noted. Currents ranged from very strong to moderate and visibility was always high.
Sites like this are what I live for! A random stretch of reef, picked more-or-less at random from Google Earth, with astoundingly high & healthy hard corals for half a kilometer. I don't even have anything negative to say about the site... it was that good! One of my top three sites we visited in all of Raja Ampat.
Site Eight Site Walkthrough
Site Eight Site Data
Site Nine
December 21
A mix of hard & soft corals occupy the reef flat beneath the mangrove forest at Site Nine
Site Nine is a jagged fringing reef consisting of two peninsula-shaped formations and the sheltered portions of reef inbetween and at either side of them. The reef's edge is lined with mangroves and frequently changes in topography but generally consists of a short upper fore reef that begins at 2-3m deep and gives way to steep sandy slopes. At the two outermost edges of the tip of the peninsula, there are wide terraces. Hard coral cover waxes and wanes, with several areas dominated by branching Acropora & Anacropora or foliose Echinopora. A large COTS outbreak and nutrient indicators were present. Currents were moderate to non-existent & visibility ranged from high to low depending on tannin-infused freshwater runoff from the mangroves.
After the underwhelming Mangrove Reef, I wasn't expecting much from Site Nine, especially considering that this site was an exploratory site picked off of satellite imagery. And despite a devastating COTS outbreak (and a constant fear of running into crocs), I was quite impressed by the hard corals at this site! Little did I know that the next exploratory site would get even better...
Site Nine Site Walkthrough
Site Nine Site Data
Site Ten
December 21
A thriving carpet of branching corals flourishes in the sheltered waters of Site Ten
Site Ten is a short stretch of mangrove-lined fringing reef sheltered within a limestone island. This fringing reef, like many others in West Waigeo, consists of a thin upper fore reef that begins at ~2m deep and gives way to steep sandy slopes, though there are some sections with a decent reef flat. Coral cover was generally moderate to high and dominated by branching Acropora. No notable currents were present & visibility ranged from high to low with a layer of brown freshwater often obscuring it so bad that the site was split between two separate drops.
Wow! Now this is what I was hoping for when folks online described the intersection between hard coral & mangrove ecosystems at Raja Ampat... it just wasn't in the popular area that I expected it to be. If only I wasn't on the lookout for crocodiles the whole time!
Site Ten Site Walkthrough
Site Ten Site Data
Site Eleven
December 21
Lush coral gardens dominated by thin branching Montipora are characteristic of Site Eleven's shallow reef
Site Eleven consists of a semi-exposed fringing reef on a limestone island with a corner that turns into a silty, sheltered mangrove-lined bay. The shallow reef flat and upper fore reef have high hard coral cover dominated by branching Montipora & Acropora
above a gradual sandy slope. Colonies were generally healthy with few negative indicators until the protected areas, where significant signs of mortality were present. Currents ranged from very strong to non-existent and visibility was very high until the mangrove area where it dropped completely.
This reef was stunning! Though I may have been biased by the excellent visibility and lighting (which admittedly was likely cancelled out by the constant fear of crocs...), I adored the dense and colorful hard coral cover at Site Eleven. The epaulette shark (Hemiscyllium freycineti) swimming uncharacteristically in the daytime was the icing on the cake! What a way to end our last site of West Waigeo.
Site Eleven Site Walkthrough
Site Eleven Site Data
How to Visit the Corals of West Waigeo
Like with many of the locations on this website, and in Indonesia in particular, visiting the hard corals of Raja Ampat is quite the challenge. The usual woes of getting to the region, planning one's logistics, bringing the right gear, and having the in-water skills required are tough here. Finding sustainable dive & snorkel operators who will accompany you to the specific sites & depths with the highest coral cover can be even harder.
Lets focus in on that last sentence— sustainable. It's no secret that the dive & snorkel travel industries (and to a lesser extant, all travel in general) have an undeniable negative impact on hard coral environments. This is especially applicable in Raja Ampat, where largely unrestricted tourism has caused near-irreversible harm via sewage, mechanical damage, and development.
Absolutely no one who isn't contributing to the conservation of these reefs in a significant way should be visiting if their visit are causing measurable harm to the integrity of the ecosystem present. This is something I take very seriously which will be reflected in the recommendations below. If sustainable means are not present, this section will be unavailable indefinitely.
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DISCLAIMER: This blog post does not constitute scholarly research, nor is it partnered with or associated with any scientific research, institutions, journals, publications, or scholars. All observations are qualitative and informal, observed during standard recreational activities without accordance with scientific norms, methods, accreditation, training, or procedures. These observations are presented only as blog posts intended for environmental enthusiasts on Rafsreefbrief.com. All blogs and observations are not submitted to nor meant for use by any scientific publications or purposes, and are not meant to support any scientific truth, conclusion, profit, or technology. Observations are only valid at time of occurrence. All opinions expressed are our own. We are not liable for any damages or losses resulting from the use ore reliance of information contained on Rafsreefbrief.com or its media accounts. Seriously people, this is just an environmental-travel hobby & blog, nothing more!