Meet the site
Imperieuse Reef is the south-westernmost of the three atolls, about 18 x 8 km, with Cunningham Island — a bare 3.7 m sand cay carrying one of Australia's two stainless-steel lighthouses — at its northern tip. Captain Rowley first sighted this reef in 1800, and Phillip Parker King named the shoals after him in 1818. It forms part of the State Rowley Shoals Marine Park.
Liveaboards dive its walls, passages and lagoon, though fewer site names are published than for Clerke and Mermaid.
About the Rowley Shoals: three shelf-edge atolls — Mermaid, Clerke and Imperieuse reefs — rise from 300–700 m depths on the edge of the continental shelf about 260–300 km west of Broome. Mermaid Reef is protected in the Commonwealth Mermaid Reef Marine Park (a no-take national reserve); Clerke and Imperieuse form the State Rowley Shoals Marine Park, with sanctuary zones and limited recreational fishing areas. Clerke carries Bedwell Island and Imperieuse carries Cunningham Island and its lighthouse. More than 200 coral species and 700 fish species have been recorded, and only a few hundred divers visit each year in a season of a few weeks. The 2024–25 marine heatwave hit hard: AIMS surveys in April 2025 found very high (61–90%) coral mortality at Mermaid and Clerke across all habitats to 30 m, so hard coral cover is currently much reduced, although fish, sharks and the drama of the walls and drifts remain.
Planning notes: Advanced Open Water certification is recommended and the site is rated intermediate. Expect to spend most of the dive around 18 m, with a maximum of about 40 m. It can only be reached on a multi-day expedition or liveaboard, so it is usually one of several sites dived on the trip and choices are made by the crew on the day. Currents are significant, so timing around the tide is part of the plan. Best season: September–December (most trips October–November). Traffic: remote/expedition only.
What you might see
Reef sharks, pelagics, turtles, reef fish, corals
Location
South-westernmost Rowley Shoals atoll (18 x 8 km) with Cunningham Island and its stainless-steel lighthouse; walls, channels and lagoon.
Facilities nearby
None – all services on the liveaboard (departures from Broome).
Before you make plans
Conditions, access and operator schedules can change. This is a location guide, not a dive plan. Ask a local operator about current conditions and suitability for your training and experience.
Sources & further reading
en.wikipedia.orgdivernet.comdiveplanit.comdivernet.comdive-the-world.comRecord updated 27 Sept 2026. Source claims are being reviewed.