Corinne's Canyon is a deep reef wall well south of the Norah Head boat ramp, reached only by boat and only in conditions calm enough to launch across the exposed beach ramp in the first place — a combination that keeps it firmly in club and experienced-diver territory rather than a mainstream charter destination. The wall itself runs broadly east-west, with its top sitting in the 21-28 m range and the base dropping to around 31 m, deep enough that dive time is genuinely limited by no-decompression constraints even for well-practised divers. Two smaller secondary walls, each only about a metre high, create miniature canyons alongside the main face, and a scattered boulder formation nicknamed The Seven Apostles adds further structure to explore along the route.Fish life at Corinne's Canyon has been described by local divers as not especially prolific compared with some of the area's shallower reefs, so this is a site valued more for its topography, depth and relative solitude than for guaranteed big schools of fish — though yellowtail, seapike, bream, leatherjackets, blue gropers, one-spot pullers and silver sweep are all recorded here, and an aggressive resident cuttlefish has made an impression on at least one visiting diver.

About 20 m east of the main wall the reef gives way to sand, marking a natural turn point for the dive. Given the depth, remote launch point and lack of scheduled charters, this is a site for a well-organised private-boat trip with a crew who know the mark, rather than one to expect to book through a standard dive centre.

Launch from the rough Norah Head beach boat ramp (only suitable for smaller, lighter boats in calm conditions) and run about 6 km south to the mark; typically dived by Norah Head Divers Depot or Terrigal Underwater Group members on private boats.

Boats launch straight across the beach into open ocean from Norah Head's rough boat ramp, so any meaningful swell or onshore wind makes launching and retrieving the boat difficult or impossible — this restricts trips to smaller, lighter craft and calm-to-moderate conditions. Once at sea, the offshore reefs are exposed to swell from the north-east through south-east; look for a period of light winds and under 1.5 m swell. Visibility is best after several settled days and noticeably improves when the East Australian Current pushes warmer, clearer water down the coast; a cold-water upwelling or recent blow brings green, sediment-laden water instead.

Descend to the wall top around 21-28 m, follow it east-west past the two small secondary walls and the Seven Apostles boulder formation, dropping to 31 m at the base, then work east about 20 m to where the bottom turns to sand before ascending; keep bottom time to about 20 minutes given the depth.

Norah Head Divers Depot runs boat charters to the offshore reefs from the Norah Head boat ramp; Terrigal Underwater Group club members also dive these sites regularly from private boats.