Aldinga Beach is one of the few beaches in Adelaide that you can drive on with an ordinary car if you are careful. Check tides and avoid soft & churned up sand if you plan to take advantage of this activity. Access is via a boat ramp.
Check the council link below to obtain a permit to avoid a fine! Note there are seasonal closures, and Australia Day is always very busy.
The coastal cliff walk from Port Willunga Beach to Aldinga Beach is unique. Unlike many Adelaide beaches, the Port Wilunga Beach is at the foot of rocky, sandy cliffs. Plenty of sets of stairs connect the cliff path with the beach along the way.
See website for map.