Fosters Beach is barely a beach at all: an 80 m strip of steep rock at the foot of the Mornington bluffs, reached by the same walking track that serves the better-known Fossil Beach to its south. The Scuba Doctor lists it as a 1–8 m shore dive with the practical caveats that it faces west, is exposed to strong westerly winds and waves, and has deep water close in at high tide with rips when waves break. Underwater it is a continuation of the cliff-foot reef that lines this coast – sandstone slabs and boulders shed from the bluffs, undercut ledges, brown algae and Sargassum on the rock tops and seagrass filling the sand pockets – shelving to about 8 m within a hundred metres of shore.

The life is that of the eastern bay's rocky shores: magpie perch, old wives, zebrafish, leatherjackets, hulafish in the gutters, decorator crabs and octopus under the slabs, abalone in the shade, and rays and flathead on the sand. Cuttlefish move inshore in winter and the ledges are worth checking with a torch. Nobody dives Fosters Beach for its own sake; it is one segment of a roughly kilometre-long stretch of cliff-foot reef from Coral Cove to Fossil Beach that a self-sufficient diver can explore in sections, using whichever entry is most convenient and calmest.

Its steep access and rocky entry make it the least attractive of the three, and on anything but a flat day the exit over weed-covered rock is unpleasant. On a calm winter morning, however, it gives quiet, clear water over unvisited reef with the bluffs as a backdrop and the Fossil Beach track as a reasonable way back to the car. It is a site for experienced shore divers who enjoy low-key exploration and are comfortable with rock entries, not for training groups or anyone wanting facilities.

From Mornington take the Esplanade north for about 2 km to the small car park opposite 631 Esplanade, which serves the Fossil Beach walking track. The track drops steeply down the bluff for about 100 m and then branches: north to Fosters Beach, south to Fossil Beach. It is a steep carry with gear and a slow climb back.

The beach is almost entirely rock, so enter carefully over the platform at high tide when there is deep water close in. Exit the same way or, in calm water, swim 300 m south and exit at Fossil Beach.

A west-facing rocky beach exposed to strong westerly winds and waves, as the source states; rips form when waves are breaking and the rock entry becomes dangerous in any swell. Dive only on light easterly offshore winds or dead calm, at or near high tide when deep water lies close inshore and the platform is covered. No current.

Avoid after heavy rain when the cliffs shed sediment. Check Fossil Beach tide times before committing, because a falling tide exposes sharp rock along the exit.

Enter over the rocks at high tide, descend in 2–3 m and head straight out to the 5–8 m contour, then turn south and follow the rubble edge toward Fossil Beach with the shore on your left. Turn at half gas or at Fossil Beach, come back along the shallower ledges at 3–4 m and surface off the Fosters entry.

No regular operator – independent shore divers only.