The Pamilacan Marine Sanctuary is a no-take zone established off the island's western shore, protecting a section of the coral reef that rings the island. The snorkelling here is good rather than spectacular — visibility is usually clear, the coral is healthy, and the fish life is diverse including parrotfish, angelfish, clownfish, and large grouper. The sanctuary is well marked with buoys and the islanders take violations seriously.
Equipment can be hired in the village — masks, fins, and snorkels are usually available. The sanctuary is a short paddle by banca from the beach and the water is shallow enough near the reef's edge for confident non-swimmers to participate with floats. The reef drops off more steeply on the outer edge and is suitable for divers, though Pamilacan is not primarily a dive destination — Balicasag Island nearby has more consistent conditions for scuba.