McKay's Shaft appears on the Cave Divers Association of Australia's register of Mount Gambier sites with a Cave rating and the note 'site is currently CLOSED'. No description, depth, dimensions or landowner details are published on the listing, and no other source consulted documents the site in detail.

What the grade tells us is useful in itself. A CDAA Cave rating means the site involves a genuine overhead environment beyond the daylight zone, where divers must run a continuous guideline to open water, apply the rule of thirds to gas, carry three lights and hold the Cave grade. That places McKay's Shaft in the same bracket as Allendale East Cave, the Engelbrecht East passage, Mud Hole and Baker's Cave. The name suggests a shaft-type entrance – common across the region, where narrow solution tubes open into flooded chambers below paddocks and forest, and entry is by ladder or rope.

The row is included for completeness because the site is on the official register and occasionally appears in older site lists and dive logs. Closures in the Mount Gambier region usually reflect changes in land ownership, landowner insurance requirements or breaches of access conditions, and some sites have reopened after the CDAA negotiated new arrangements. Until then, McKay's Shaft is off limits, and divers should not approach landowners directly – enquiries go through the CDAA. If it reopens, expect it to suit CDAA Cave-rated divers with vertical-access experience. Divers planning a Mount Gambier trip will find plenty of open Cave-rated alternatives nearby.

McKay's Shaft is listed by the CDAA as a Mount Gambier Cave-rated site but is currently closed and no access details, landowner or booking system are published. Do not attempt to locate or enter the property. Watch the CDAA dive-sites page and member communications for any reopening, which would include directions, parking, vertical-access requirements and key arrangements.

Mount Gambier has fills, accommodation and the Lady Nelson Visitor Centre for keys to other open sites.

Unaffected by swell or tide. Access and surface conditions on private farmland are the limiting factors: Total Fire Ban days may restrict access or compressors, summer heat makes vertical exits hard work, snakes are active in warm weather and winter rain turns farm tracks muddy. Underwater conditions are stable, with groundwater at a constant ~15°C.

The site is closed regardless of conditions.

Not applicable while closed.

CDAA grade: Cave – site currently closed. No published depth or penetration data.

None – site closed (CDAA).