Barracuda Lake

Your gear goes on your back at a white-sand cove and stays there for fifteen to twenty minutes, up a staircase and along a wooden walkway threaded between limestone blades sharp enough that divers remember them afterwards. The lake opens out at the end of it, closed in on every side by cliffs. Then you get in and the rock keeps going. The blades and pinnacles of the island carry on under the surface, so the walls and the floor are a stone forest too1.

The first few metres of the descent are dark and nearly opaque, and then they clear as you sink. Below that the visibility is the best in Coron, fifteen to twenty metres routinely and thirty on a good day, which is the opposite of what the bay wrecks give you.

At about fourteen metres the dive changes twice at once. The fresh water on top gives way to sea water, and the temperature climbs from around 28 °C to roughly 38 °C2. You can usually see the boundary as a shimmering line before you cross it, and once you are through it the water feels thick. Fresh water is lighter than sea water, so you get more buoyant on the way down. That is backwards from every other dive you have done, and it is the real skill the site asks for.

The warm layer runs to roughly twenty-six metres, and this is where the dive actually happens: between boulders, sunken tree stumps and fins of grey rock, in water that nothing much lives in. Below that it cools again3, the tannin thickens, and the floor arrives at about thirty-five metres2. It is not sand. It is a fine brown ooze that takes a fin kick and holds it, and in a lake with no current nothing you disturb settles quickly. A cave mouth sits between thirty and thirty-three metres, running about thirty metres back and wide enough for one diver, with water moving through it between the lake and the sea. That is a technical dive and no part of the normal one.

A lake sitting a little above the sea, on an island made of dissolved rock, with a way through to the sea at the bottom of it. Coron Island is limestone4, weathered by tropical rain into blades and hollows until the whole island reads as a stone forest, and this lake is a flooded piece of it. Not a volcanic crater. That claim follows the site everywhere and there is nothing under it.

What is genuinely odd here is not the heat, it is that the lake is still a lake. It connects to the sea through dissolved conduits, and it sits slightly higher than the sea and drains outward, which is what keeps the fresh water on top and keeps the tide out of it1. That single arrangement explains the whole dive. It explains the two layers, the line you can see between them, and the barracuda that shows up now and then, which comes in through the same connection and leaves again.

Divers reach for the same comparison without knowing any of the geology, and the comparison is the moon. Grey rock, brown floor, almost nothing alive, and a temperature doing what temperature is not supposed to do. It splits opinion cleanly. Some divers call it the strangest dive they have done and some find it dull, and both reactions are common. The ones who tend to name it as the thing not to skip are the wreck divers, four days into a week of steel, who wanted one dive that was about something else.

Wear less, not more. A swimsuit or a 3 mm shorty is right here, and a full suit is a liability in the warm layer. Every other site in Coron pushes you the other way, towards 3 mm and 5 mm for repetitive deep days. This is the one place where that advice reverses.

Weight yourself for fresh water and expect that to stop being true halfway down. You enter fresh and finish the descent in sea water, so the correction lands halfway down the water column and not on the bottom.

The walk in is what people underestimate. Fifteen to twenty minutes with a cylinder on your back, up a staircase and along a walkway in tropical heat, and then straight into water at body temperature for the rest of the hour. Drink before you carry.

Go early or go late. The lake is a fixture on the island-hopping route and the entry area fills up, with swimmers in life jackets in a roped section at the surface. One diver describes arriving at midday to one other group and leaving with about fifty people in the water.

The island, its lakes and the water around it are Calamian Tagbanwa ancestral domain, and the lake is visited on the community's terms. A charge is collected at the water, separately from the municipal tourist fee. What people report paying differs widely, and one account records paying nothing, so ask your operator what your trip already covers.

Then the part that is easy to leave too late. No working recompression chamber is confirmed anywhere in Coron. The nearest one reported working is at Puerto Princesa, which shares the province and is still awkward, because no airline flies Busuanga to Puerto Princesa direct and the scheduled route runs through Manila. The access that makes this dive charming is the same access that makes an evacuation slow: a casualty has to come out of the water, back along the wooden walkway, down the staircase and onto a boat for the run to town. Hold insurance that pays for hyperbaric treatment and for the flight, and check the boat carries oxygen.