Meet the site
Cockatoo Reef in the Pompey Complex holds one of the few blue holes on the Great Barrier Reef. Research on the Pompey reefs describes two such holes, at Cockatoo and Molar reefs, both roughly circular, 240-295 m across and 30-40 m deep, surrounded by lagoon depths of 5-10 m. They are interpreted as collapsed dolines (sinkholes) formed during low sea-level periods, then partly filled with sediment and colonised by coral as the sea rose after the last ice age. At Cockatoo, the hole is completely rimmed by living coral, and its inner slopes drop at 60-70° to about 25 m before easing towards the floor. The Marine Life Network describes the Cockatoo blue hole as suitable for less experienced divers, lying inside a shallow 10 m lagoon that is exposed at low water, with limited fish life inside the hole itself. Staghorn and other corals cover the rim, and the outer reef supports sharks and pelagic fish. Reaching the Pompeys is the main challenge: they lie far offshore from Mackay, in an area known for the fastest tidal streams on the reef, and there is no regular dive operator. Visits are by expedition charter or capable private boat, timed for neap tides and calm weather. The site is a geological curiosity as much as a dive, and it suits divers with Advanced certification who are part of a self-sufficient expedition.
Research this site before booking Stored site notes may be historical. These questions highlight gaps without turning old instructions into a current dive plan.
Cockatoo Reef Blue Hole (Pompey Complex) is recorded as Sinkhole/Cenote in Swain Reefs. The listed access is boat (multi-day/liveaboard). Confirm the actual meeting point, route and permission to visit; a map pin does not establish any of these.
Topics flagged by the stored research
These are questions prompted by the existing notes, not a verified or complete hazard assessment.
- Current and timing
- Ask how the operator assesses the current window for the actual route. Historical tide notes are not a departure instruction.
- Planned depth
- Confirm the intended route and training requirements; the recorded maximum is not a target.
Historical access notes exist for this record, but have not been independently verified for current use. Request current directions from the operator or site manager rather than following an old entry description.
Questions, answered
Is Cockatoo Reef Blue Hole (Pompey Complex) suitable for my certification?
The record lists Deep/Advanced + experience. That does not establish suitability for every route or day. Share your training, recent experience and equipment needs with the operator and ask about the specific proposed dive.
Can I book Cockatoo Reef Blue Hole (Pompey Complex) through YouDive?
YouDive is an independent research directory. Contact an operator directly to confirm whether it currently runs the trip, the inclusions and the booking terms.
What you might see
Staghorn and other corals on the rim, limited fish inside the hole, reef sharks and pelagic fish on the outer reef
Location
A roughly circular drowned doline 240-295 m across and 30-40 m deep inside a shallow (5-10 m) lagoon on Cockatoo Reef in the Pompey Complex, completely rimmed by living coral.
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
researchdata.edu.aumarinelife.org.auRecord updated 27 Sept 2026. Source claims are being reviewed.