Meet the site
The reef below O'Hara Bluff is a gently sloping kelp-covered reef between Pirates Bay and Fortescue Bay. The Marine Life Network guide describes it as O'Hara Reef in 10-20 m, with a kelp garden and crayfish. Historically this stretch of coast supported dense forests of giant kelp (Macrocystis pyrifera), which grows from the reef to the surface in columns and forms a floating canopy. Those forests have almost disappeared: scientists estimate a 95 per cent loss of giant kelp on Tasmania's east coast since the 1950s, driven by warming water carried south by a strengthening East Australian Current, low nutrients and overgrazing by the long-spined sea urchin. The Tasman Peninsula has become a focus of efforts to protect the remnants and restore what has been lost. Researchers from the Institute for Marine and Antarctic Studies have grown giant kelp from seed and grafted it onto reef here, producing a 3,500 square metre kelp field after 18 months that survived a marine heatwave, and Eaglehawk Dive Centre now runs a winter internship in which divers learn restoration techniques. What divers see at O'Hara Bluff therefore varies from year to year. In good years the canopy is thick enough to swim through the stipes with sunlight filtering down, and the understorey shelters weedy seadragons, wrasse, leatherjackets, magpie morwong and rock lobster. In poorer years the reef is dominated by shorter brown algae such as crayweed and Ecklonia, still pleasant but without the cathedral effect. Fur seals from nearby colonies often join divers in the shallows, playing in the kelp. It is an easy, shallow dive suitable for all levels. Ask the dive centre about the current state of the kelp and respect restoration plots.
Research this site before booking Stored site notes may be historical. These questions highlight gaps without turning old instructions into a current dive plan.
O'Hara Bluff Kelp Forest is recorded as Kelp Forest in Tasman Peninsula. The listed access is boat (day trip). 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.
- Lines and obstructions
- Discuss any known entanglement concerns and the suitability of the planned area.
- Water movement
- Ask how swell and local exposure affect the proposed entry, exit and route.
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 O'Hara Bluff Kelp Forest suitable for my certification?
The record lists Advanced 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 O'Hara Bluff Kelp Forest 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
Giant kelp (Macrocystis pyrifera, variable), crayweed, Ecklonia, weedy seadragons, blue-throated wrasse, leatherjackets, magpie morwong, southern rock lobster, sea urchins, fur seals
Location
Gently sloping kelp-covered reef under O'Hara Bluff, on the Tasman Peninsula coast between Pirates Bay and Fortescue Bay.
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
marinelife.org.auabc.net.auabc.net.auxray-mag.comindopacificimages.comRecord updated 27 Sept 2026. Source claims are being reviewed.