Skillion Cave sits beneath the landmark Skillion headland at Terrigal, and despite its name it's better understood as a large gutter or crack roofed by a wedged boulder slab rather than a true cave — the overhead is created by a huge rock lodged across the top of the crack, with smaller overhangs on either side inside. The wall here zig-zags as it follows the contour of the rock platform, running initially north-west and then west toward the gutter entrance, with depth building from around 8 m near the entry to almost 20 m inside the feature itself, making this one of the more demanding shore-accessible dives on the Central Coast.Terrigal Underwater Group rates it among the best shore dives in NSW, and the appeal is a genuine sense of enclosed topography rarely found this close to shore: divers work along a shallow ledge at about 10 m on the northern wall before dropping into the gutter's deeper, more confined section, watched over by resident blue gropers — usually a large male and several smaller brown females — along with ladder-finned pomfret, yellowtail and jewel anemones dressing the rock. A large bullray has also been recorded patrolling north of the cave entrance.

Because the site sits directly below an exposed headland, it is genuinely conditions-dependent: swell from the east or north-east both complicates the rock-platform entry and stirs up surge inside the gutter, so this is a dive to save for a calm day with a diver who has good buoyancy control and enough gas reserve for what can be a long return leg.

Park at the small angled car park just north of The Skillion headland. Enter via a jump from the higher rock platform level, with an alternative exit onto the sloping rock about 10 m to the left/south of the entry point. Alternatively, dive it as a short boat hop from Terrigal Haven.

The shore route is a long swim (roughly 50 m north along the surface before descending) so most divers prefer entering closer to the site.

Very affected by sea conditions — swell from the east or north-east makes the rock-platform entry and exit hazardous, and surge is felt inside the cave/gutter itself even when the surface looks reasonable. Best attempted on a calm day with minimal swell; keep at least 50 bar in reserve for the exit given the length of the return swim.

Enter from the rock platform, swim north for about 50 m before descending, then follow the zig-zagging wall northwest then west toward the cave/gutter entrance, dropping to almost 20 m inside, before returning along the same wall to the exit point.

Pro Dive Central Coast (Terrigal Haven) and Central Coast Divers run regular boat charters to the Terrigal reef network; Terrigal Underwater Group club members dive the full spread of sites from private and club boats.