Sinkhole
Kilsby's Sinkhole
Basic Cave: CDAA site rating [1] (Rating for CDAA member access.). Lake portion for open water divers with approved operators: operator zone [4] (The landowner says certified open water divers may dive the 'lake' portion with the site's guides or an approved operator.). These categories are the named scheme's own; they describe the training a site calls for.
A large, very clear sinkhole on a working sheep farm south of Mount Gambier. CDAA members book dive slots through the CDAA; the owners also run snorkel and tour experiences and licence other operators.
Kilsby's Sinkhole sits on a family-owned sheep farm at Moorak, about 15 minutes from Mount Gambier. It is a large open sinkhole with a chamber extending off its south-western side; divers enter from a pontoon. The owners describe visibility of around 50 m on most days.
The site has an unusual history. Divers used it from the late 1950s, but recreational diving was stopped after a double drowning in April 1969, and defence researchers later used it for sonobuoy trials. Authorised civilian diving resumed in 1983 with the CDAA Research Group, and a 2007 lease widened CDAA access. Today the CDAA books timed dive slots for its members, while the landowners separately run snorkel tours and approve other dive and freediving operators.
The environment
A deep open sinkhole of clear, fresh groundwater with a side chamber; the floor is protected and divers must not touch it.
Conditions
The landowner describes visibility of 50 m on most days; no temperature figure is published on the pages consulted.
Typical ranges from published sources, not current conditions.
Facilities
Pontoon at water level (maximum 10 people), gear-up area, toilet and BBQ verandah for divers; no compressors or generators allowed on site.
For orientation, not navigation. Hollow dots are approximate.
Every fact on this page, with its source (12)
| Fact | Status | Source |
|---|---|---|
| The CDAA site directory rates Kilsby's Sinkhole (5L46) Basic Cave. | Verified | [1] |
| The landowner says certified and current open water divers can dive the 'lake' portion with the site's dive guides or an approved operator.Landowner statement; the extent of the 'lake' portion is not defined on the page. | Verified | [4] |
| The landowner states visibility is 50 m on most days.Self-description by the site owner. | Reported | [4] |
| A diver with at least five prior dives at Kilsby's must nominate to open a booking session, and divers book only themselves.Updated October 2025. | Verified | [2] |
| An access trial lets CDAA members share the water with other divers, freedivers and snorkellers and be charged per diver per dive slot on any day, subject to availability.Trial status as of the page's last change on 2025-10-25. | Verified | [2] |
| The CDAA booking page lists Kilsby's from AU$45.00, and the owners apply a 21-day cancellation policy with no refund inside 21 days.Page last changed 2025-10-25; viewed 2026-10-14. | Verified | [2] |
| Dive slots are 8-10am, 10am-12pm, 2-4pm, 4-6pm and 6-8pm (summer only, to be confirmed), with a maximum of 10 divers per slot and a 24-hour booking lock-out. | Verified | [2] |
| Maximum pontoon capacity is 10; compressors and generators are not permitted on site; divers use a gear-up area, toilet and BBQ verandah. | Verified | [2] |
| Recreational diving was closed after a double drowning in April 1969; authorised civilian dives resumed in 1983 with the CDAA Research Group, and a 2007 lease increased CDAA access. | Verified | [3] |
| The landowners' approved diving operators list includes Dive Experience (Mount Gambier), Diving Adelaide, Deep Blue Ventures and Blue Water Ascent, along with the CDAA and several freediving and club operators. | Verified | [5] |
| Coordinates are the Moorak locality centre, not the sinkhole.Area-level point. | Verified | [6] |
| Coordinates are the Moorak locality centre, not the sinkhole.Area-level point. | Verified | [6] |
Verified: stated by an official or primary source we opened. Reported: from a secondary source only. Sources conflict: the note gives both versions. May be out of date: the newest source we found is old.
Written in our own words from the sources above. Report a correction