Dilumacad Island (Helicopter Island)

Open reef and tunnel are different routes

El Nido Paradise lists Dilumacad Reef separately from Dilumacad Tunnel. The existing Helicopter Island guide covers the broader island context; a reef booking should not imply entry into the overhead route.

Published route information

El Nido Paradise gives the reef as 5–43 m and the tunnel as 10–15 m. These describe different features, not competing measurements of one route. Tabanka publishes additional experience and equipment conditions for its tunnel outing. Confirm those conditions directly for the specific trip.

Choose the outing explicitly

Ask whether the itinerary stays in open water and which side of the island it visits. This partial guide does not establish overhead-diving suitability, a universal qualification requirement or a surveyed island-wide depth limit. Do not use the island's general listing as permission to enter a tunnel.

Sources and review status

Tabanka Divers; El Nido Paradise. Published sources reviewed on 4 October 2026; no local-diver verification is claimed. Source publication and field-observation dates may differ from the review date.

What the tunnel account actually describes

In Thomas de Reviers's El Dive article, published in October 2016 and subsequently updated, the tunnel lies along the limestone cliffs on Helicopter Island's north face. He describes a horizontal passage about 35 m long, with its openings at roughly 9–11 m depending on the tide. Palawan Divers’ area page instead describes a 40 m tunnel. These attributed length estimates remain unresolved. Those measurements concern the passage and its openings; they do not replace the wider reef depths above.

The article describes rocky sides with small recesses, a sandy bottom and a larger chamber in the middle. Openings overhead admit daylight around a school of sweepers. Its named animal reports include small shrimps, pipefish, crabs, nudibranchs, morays and spiny lobsters, as well as a flashing clam. These are an older operator account of an overhead habitat, not current occupancy checks. The chamber, illuminated openings and sandy bottom explain why this is a different environment from a daylight reef outing; the description is not an entry procedure or confirmation of present access.

Open-water habitat around Helicopter Island

Palawan Divers' area guide separately describes Helicopter Island's shallow coral gardens and seagrass beds, with green turtles reported there. It places the tunnel on the northern side and lists approximately 15–20 minutes for its boat journey to the island. That travel estimate belongs to the operator's published itinerary and can change with departure point and conditions. The island-level habitat description does not identify every garden as a tunnel entrance or establish a single route connecting them. A visitor seeking seagrass or open coral scenery can therefore ask specifically for those features instead of assuming that a booking under the island's name includes the enclosed passage.