Meet the site
The Olgas are named after Kata Tjuta (formerly the Olgas) in Central Australia, because the underwater landscape reminded its discoverers of those great domed rocks. The site is a field of very large boulders interspersed with smaller ones on a sandy bottom at about 24 m, one kilometre offshore from Stack Island north of Kiama. Between the boulders are canyons and open sandy areas, creating a maze-like terrain.
The boulders carry heavy growth of sea squirts, sponges and some gorgonians. Yellowtail and silver sweep school over them, numbfish and large bull rays rest on the sand, and phyllodesmium nudibranchs and sea stars are found on the rock. With visibility around 15 m, the combination of massive shapes and colourful growth makes for dramatic scenery.
The challenge is navigation. Because all the boulders look much the same and there is no distinct wall or reef edge to follow, divers must rely on a compass and careful attention to return to the anchor. The site is also only accessible by private boat, since no charter operator works out of Kiama, which keeps it very lightly dived – a genuine off-the-beaten-track site for Illawarra boat owners. Suitable for Advanced divers with good navigation skills, it is best combined with the shallower Blind Shark Reef near Kiama Harbour for a second dive. Because the site is well offshore with no nearby shelter, boat owners should carry a dive flag, a VHF radio and a DSMB for each diver, and leave someone aboard to watch for bubbles and passing traffic. Launching from Shellharbour Marina is a practical alternative if Kiama Harbour's bar is uncomfortable, and allows the site to be combined with the Bass Point reefs on the way home.
Research this site before booking Stored site notes may be historical. These questions highlight gaps without turning old instructions into a current dive plan.
The Olgas is recorded as Reef in Wollongong & Kiama. The listed access is boat. 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.
- Other water users
- Ask about vessel activity, exclusion areas and the agreed surface arrangements.
- 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 The Olgas 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 The Olgas 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
Yellowtail, silver sweep, numbfish, bull rays, phyllodesmium nudibranchs, sea stars, sea squirts, sponges, gorgonians
Location
Field of huge and smaller boulders on sand at about 24 m, exactly 1 km off Stack Island, which lies 5.5 km north-north-east of Kiama Harbour.
Facilities nearby
Kiama Harbour ramp, parking, toilets and cafés; nearest air fills at Shellharbour Scuba and Photography Centre (about 20 minutes north).
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
michaelmcfadyenscuba.infoRecord updated 26 Sept 2026. Source claims are being reviewed.
