Meet the site
One Tree Island Reef is one of the most scientifically important reefs on the Great Barrier Reef, but it is not a recreational dive site. The reef, about 5.5 km by 3.5 km with a rubble and shingle cay at its eastern end, lies about 96 km north-east of Gladstone and is home to the One Tree Island Research Station, managed by the University of Sydney since 1974. The reef sits within a Scientific Research (Orange) Zone, one of only two such no-entry zones in the entire Marine Park (the other is near the Australian Institute of Marine Science off Townsville). The zone exists so that long-term research and monitoring can be carried out without disturbance, and compliance officers have publicly reported recreational vessels detected transiting it without permission. Research at One Tree has produced more than 400 published papers on climate change, coral bleaching and reef ecosystems, and the reef's shallow rhodolith beds and enclosed lagoons make it a natural laboratory. The station hosts educational groups of up to about 30 senior high school and university students for field training, which is the only practical way for most people to visit. For divers, the relevance of One Tree is as context: the healthy condition of the surrounding Capricorn reefs is monitored here, and much of what is known about reef responses to warming and storms in this region comes from this station. It is included in this database because it appeared in the first pass as a dive site; it should be treated as closed. Divers wanting similar remote Capricorn reef experiences should look at Sykes, Fitzroy or Lamont reefs instead.
Research this site before booking Stored site notes may be historical. These questions highlight gaps without turning old instructions into a current dive plan.
One Tree Island Reef is recorded as Reef in Heron Island & Capricorn Group. 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.
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 One Tree Island Reef suitable for my certification?
The record lists Open Water. 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 One Tree Island Reef 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
Reef sharks, turtles, giant clams, pelagic fish, hard corals, rhodolith beds, nesting seabirds (research records)
Location
A 5.5 x 3.5 km closed-lagoon reef about 96 km north-east of Gladstone, south-east of Heron; home to the University of Sydney research station and one of only two no-entry Scientific Research (Orange) Zones in the Marine Park.
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.orgmiragenews.comsydney.edu.auRecord updated 26 Sept 2026. Source claims are being reviewed.