Cervera Shoal
Also known as: Cervera Reef, Snake Island, Spaghetti Reef, Spaghetti Shoal
A seamount 10 km southeast of Panglao with banded sea kraits in numbers on a plateau at 12 metres, dived as a drift when the current allows.
Last updated August 2026
The dive
Nothing resolves under you on the way down. The boat runs southeast from Alona for half an hour to an hour, the guide puts you in on the side the current is coming from, and you descend through blue water with no visual reference until the plateau appears below12. Divers who have never done it find it the hardest part of the dive.
The current sets the shape of what follows. It runs hardest at the surface and gets mellower as you go deeper3, so the effort is often over by the time the top of the shoal arrives at around 12 metres. After that you stop swimming and let the plateau pass beneath you.
What passes is not a coral garden. Coral rubble, sea urchins, big bucket sponges, soft corals and feather stars cover the top, and the banded sea kraits work the rubble and the crevices for eels. On a good day the count runs to dozens. Then the edge arrives, where the plateau falls away past 60 metres1 and guides turn and watch the open water.
The exit is a boat pickup, not a swim back. You come up on an SMB somewhere down current of where you went in, and the outrigger comes to find you.
What makes it special
Cervera is the Panglao dive that gets called off. Centres here treat it as a special trip, say plainly that it is not dived every single day, and give it a miss when the current is up12. Nothing else on the island is sold that way. The shoal stands alone about 10 km southeast of the beach3 with no coast to hide behind, so the island trick of moving to whichever shore the wind is off does not work out here.
What is worth crossing open water for is one animal. Banded sea kraits appear on several Panglao reefs, singly, as one line in a list of critters. Here they are the reason the boat goes at all, and the working name Panglao guides use for the place.
They are venomous and that is not the whole picture. The venom is neurotoxic and it acts fast on eels, which are close to the entire diet, so the animal is working the same holes a diver is peering into4. It is also extremely reluctant to bite a person even when provoked, and no human fatalities from this species have been recorded4. Both halves hold at once, and what follows from that is manners, and not fear.
Photographer's notes
Macro is the published recommendation, and the nudibranchs are why3. Sponges and rubble hold most of what is worth stopping for, and stopping is the problem: this is a drift, and the plateau moves past you at whatever speed the day has set.
Say at booking that you are shooting. At least one shop builds the boat day around a photographer's target when it knows in advance, which matters at a site that only runs when the sea allows it1.
One rule belongs to this dive and no other. Kraits are air breathing and have to go up to breathe4, so never put yourself or a lens between one and the surface, and never follow one that has started climbing1.
Know before you go
Advanced Open Water is the practical floor, and it is the current that puts it there, not the depth. Centres recommend the site for advanced divers only5 and some decline anyone below that. What actually gates you is drift experience and an SMB you can deploy from depth, because you finish the dive somewhere the boat has to come and find you.
Stay off the plateau top. Sea urchins cover it exactly where the dive is shallowest5, so hover through that section instead of settling on it, and keep your trim on the rubble.
Settle the emergency chain before the boat leaves. This is a dive 10 km out, with a boat ride of 30 to 50 minutes back to the beach. The coast guard sub-station for these waters is on Panglao itself, in Barangay Tawala at the Alona end of the island, on 0927-350-54846. The hospital with an emergency department is Gov. Celestino Gallares Memorial Medical Center in Tagbilaran City, across the bridges. A hyperbaric chamber exists on Panglao and whether it is staffed and running is a separate question, so ask your operator where that stands, and make sure your insurance covers hyperbaric treatment.
Why Dive Cervera Shoal
What makes this dive site stand out.
- Banded sea kraits in numbers
Dozens over the rubble on a good day, hunting eels in the crevices
- Offshore seamount
A plateau standing alone in open water about 10 km southeast of Alona Beach
- Not dived every day
Centres treat it as a special trip and call it off when the current is up
- Blue water descent
No visual reference on the way down until the plateau resolves below you
- Rubble, not a coral garden
Urchins, bucket sponges, soft coral and feather stars over a rubble top
Depth & Profile
Location
9.4895°N, 123.8459°E
Conditions & difficulty
Summary
Current and exposure set the rating, not depth. An open water crossing of 10 km to a site with no lee, a current that runs hardest at the surface and eases below, and a descent into blue with nothing to look at until the plateau resolves.
Safety considerations
What can go wrong here, and what divers do about it. Conditions change - take the briefing from the operator on the day.
- Current: Strong sweeping current over an exposed seamount, hardest at the surface and easing with depth. The site is dived as a drift.Go in on the side the current is coming from, let the plateau pass beneath you, and carry an SMB for the surface pickup
- Depth: The descent runs through open water with no visual reference until the plateau resolves below.Hold neutral and descend on a guide reference, never by feel
- Marine life: Banded sea kraits in numbers, hunting the crevices a diver is looking into. They are air breathing and must go up to the surface.Let one pass, never handle or corner one, and never put yourself or a camera between a krait and the surface
- Structure and sharp edges: Sea urchins cover the shallow top of the plateau, which is where the dive is shallowest.Hover, do not settle, and stay off the structure through the shallow section
- Remote location: 10 km offshore, half an hour to an hour by outrigger from the beach, with no shore option and nothing to swim to.Guided boat tended dives only, an SMB on every ascent, and insurance with hyperbaric cover
Marine Life
Regulations
No protected-area designation, permit, quota or closed season applies to this shoal. The island's protected seascape is made of surveyed blocks anchored on Panglao's north and west shores, and the shoal lies about 10 km to the southeast of them.
Frequently Asked Questions
Why do dive shops cancel Cervera Shoal so often?▾
Because it has no lee. The shoal stands alone in open water about 10 km southeast of Alona, so there is no sheltered side to move to when the current or the swell picks up, which is the trick Panglao centres use on the island's own coasts all year. The result is that Cervera is not a scheduled dive but a conditional one: shops describe it as a special trip, decide on the morning, and drop it whenever the current is running. Plan for it into the early days of a trip and never leave it for the last one, and treat a Pamilacan boat day as the realistic route to it.
What makes Cervera Shoal an advanced dive when the top is only 12 metres down?▾
Three things that have nothing to do with depth. The crossing is 10 km of open water to a site with no shelter. The current runs hardest at the surface and eases as you go deeper, so the surface, not the bottom, is where the dive is hardest. And the descent goes through blue water with no visual reference until the plateau appears underneath you, which is a matter of skill that no certification teaches. Centres recommend the site for advanced divers only and gate it on drift experience, and being able to send an SMB up from depth counts for more here than the card in your wallet.
Why is Cervera Shoal called Snake Island?▾
For the banded sea kraits, not for a landfall. The dive is on a submerged plateau whose top sits around 12 metres down, and the name is the one Panglao guides use for the place because of what lives on it. It also collects a second nickname, Spaghetti Reef or Spaghetti Shoal, which is a description of how the reef looks when a lot of black and white banded animals are moving over it at once.
Are the sea snakes at Cervera Shoal dangerous?▾
Both halves of the answer are true. Banded sea kraits are venomous, the venom is neurotoxic, and it works on the eels that make up almost the whole of their diet. They are also extremely reluctant to bite people even when provoked, and there are no recorded human fatalities from this species. Their mouths are small and they show very little interest in divers. You will also see the venom's strength set against other snakes as a multiplier. Those comparisons rest on nothing measured and are not worth planning around. What matters underwater is etiquette: let one pass, do not corner or handle it, and remember it has to reach the surface to breathe.
How deep is Cervera Shoal?▾
Published figures for the top of the plateau run from 8 metres to about 12, and the difference is the slope of the shoal itself, not a disagreement about where the top sits. The dive itself normally works between 12 and 30 metres, and the published range for the site as dived is 8 to 35. Below that the structure keeps going past 60 metres into open water, which is not a recreational feature and not somewhere a drift dive should carry you.
Can you see whale sharks or mantas at Cervera Shoal?▾
Occasionally, and it is not a reason to book. Both are put down to luck: no month, no window and no sighting rate attaches to either, and nobody says which manta it is. What the shoal delivers is the kraits, plus water deep enough off the edge that guides do turn and look outward. Treat anything in the blue as a bonus on a dive that already has a reason to exist.
Is Cervera Shoal protected, and do you need a permit to dive it?▾
No to both. Travel copy sometimes describes the shoal as a refuge for the snakes, which describes what the animals do there and is not a designation. Panglao island itself carries a protected seascape, but it is made up of surveyed blocks anchored on the north and west shores, and this shoal lies about 10 km away to the southeast of them, outside all of it. There is no permit, no quota, no closed season and nobody on the water here, and the only thing rationing access is the weather.
References
- 1.Sierra Madre Divers, April 22, 2026 — Cervera Shoal: Bohol's Best-Kept Secret for Sea Snake Encounters
- 2.Seaquest Dive Center — Pamilacan Island
- 3.Scotty's Action Sports Network — Cervera shoal dive site is also known as the Snake Island
- 4.Animal Diversity Web, University of Michigan Museum of Zoology — Laticauda colubrina
- 5.Alona Bohol Divers Club — Dive Sites in Snake Island
- 6.Philippine Coast Guard — Coast Guard District Central Visayas
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