Whale bones is in Encounter Bay at Victor Harbor.
This is a big system of limestone caves, undercuts, swim-throughs, and reef. It is a virtual honeycomb of caves, and passages
The top of the reef is only in about 2-3 metres of water, with lots of holes in the top, that lead down into the caves.
Follow the road to the bluff and turn off at the hospital. Whale bones is the reef in front of and to the right where this road meets the beach.
Access is from shore over a 100 or so metres of knee deep water or by boat from the nearby Bluff boat ramp.
If you head out to sea, you will also see a drop-off, which also leads into the caves. The site got its name from the fact that there used to be lots of whale bones in the area, as the whalers used to dump the whale carcasses in the area.