Forster Pinnacle is a submerged rock mount with gutters, large flat areas and wall features sitting in the middle of an otherwise sandy bottom. Bare rock dominates the shallower areas which may be subject to surge, while sponge and brown algae encrust the sheltered corners and gutters. Forster Pinnacle has been identified as one of the primary grey nurse shark aggregation sites on the East Coast. Historically the Forster Pinnacle was subjected to commercial fishing activities for wobbygong sharks and grey nurse sharks which severely depleted the populations of both species until the area was declared a sanctuary zone. Now, both wobbygong shark and grey nurse shark populations have recovered and are a significant attraction for Forster Pinnacle as a dive site. Other common large species at Forster Pinnacle are jewfish, bull rays, eagle rays and turtles. The boat ride out to Forster Pinnacle will usually provide the opportunity to see dolphins and whales from the surface.
As an offshore dive site the Pinnacle is exposed to some ocean current, although not as strong as sites further offshore such as the SS Catterthun . The shallower regions may be subject to surge, while swell can be an issue for the safety stop.
Water temperature at Forster Pinnacle varies from 15 to 24 degrees, and visibility varies from 7 to 30 meters.