Meet the site
The Arch is the best-known of the Black Rock sites, a small island off Lilli Pilli on the southern shore of Batemans Bay. Michael McFadyen describes the dive in detail: from an anchor on rocky bottom in about 10 m on the western side of the southern end of Black Rock, divers drop to the sea floor, reach a wall and follow it south past a small gutter. After crossing a section blocked by large boulders and climbing over a ridge, you arrive in a huge bowl or amphitheatre at about 15 m. The arch itself sits at around 13 m. It is quite long – almost 10 m thick at its widest – but very low. A cave extends beneath it and other caves run under Black Rock to the north and east. The maximum depth is 19–20 m off the wall.
The Marine Life Network describes a large bowl-shaped depression with an open quasi-cave about 10 m wide, decorated with yellow zoanthids, sponges and gorgonians. McFadyen notes cuttlefish and friendly blue groper, and eastern blue devilfish under the overhangs. Wobbegongs lie in the low cave areas and Port Jackson sharks are common in winter.
The Arch is sheltered and close to the ramps, so it is one of the most reliable dives in Batemans Bay and a favourite of the local operators. The swim-throughs and caves need good buoyancy, because the fine sediment silts up easily, and a torch is worth carrying. It suits Open Water divers with a guide and is a good introduction to the more complex dives around Black Rock, such as the Bubble Cave, The Tunnel and The Chimney, which can be combined as a drift.
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 Arch (Black Rock) is recorded as Cave/Cavern in Batemans Bay. 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.
- Water movement
- Ask how swell and local exposure affect the proposed entry, exit and route.
- Overhead environments
- Ask whether the plan stays entirely in open water. A wreck or cave listing is not permission or training to enter.
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 Arch (Black Rock) 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 Arch (Black Rock) 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
Blue groper, cuttlefish, eastern blue devilfish, wobbegongs, Port Jackson sharks, yellow zoanthids, sponges, gorgonians, sea squirts, silver sweep, yellowtail
Location
Long, low arch and cave in a sandy amphitheatre on the south-west side of Black Rock, off Lilli Pilli on the southern shore of Batemans Bay; 10–20 m.
Facilities nearby
Mosquito Bay (Lilli Pilli) and Hanging Rock boat ramps; air and nitrox fills at Beneath the 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
michaelmcfadyenscuba.infomarinelife.org.aubeneaththebay.com.auspiritdiversdotcomdotau.wordpress.comRecord updated 27 Sept 2026. Source claims are being reviewed.