The deep version of Dee Why Wide is the same reef approached from its seaward side, where the plateau ends in a proper wall dropping from about 30 m to a sand floor at 36–37 m. It is dived as a distinct profile because the character changes: the boulders are bigger, the overhangs at the base of the wall are deeper and darker, and the fixed growth, now beyond the reach of most surge, becomes a dense carpet of sponges, gorgonians and sea whips with none of the kelp that fringes the shallower top. Sydney Dive Charters describes it as a 'large reef, situated at the reef edge, with an excellent depth range', and Pro Dive gives 37 m as the maximum for their trips.

The wall is where the bigger animals turn up. Kingfish in numbers hunt along the edge, bull rays and the occasional eagle ray cruise the sand, grey nurse sharks are seen from time to time in the cooler months, and wobbegongs stack in the undercuts. Blue devilfish, pomfret schools and giant cuttlefish are shared with the shallower reef.

In blue winter water the view up the wall to the plateau, with the shot line disappearing toward the surface, is one of the more dramatic sights on a Sydney reef. This is a short dive. At 33–36 m an air diver has around 15 minutes of no-decompression time, and most dives are planned on nitrox or as a light-deco profile with a staged ascent; operators require Deep certification and experience.

The reward is a piece of undisturbed reef that only a few divers see each year, and the knowledge that the Myola wreck lies a few kilometres further out in the same clear water. It suits Deep-certified divers and entry-level technical divers as a progression from the Advanced profile.

Same passage as Dee Why Wide: 20–30 minutes north from Little Manly ramp or Manly Cove, 35 minutes from Roseville Bridge, 2.4 km off the north end of Curl Curl Beach. The boat positions on the eastern edge of the reef rather than the south-eastern corner and drops a shot into 30–34 m. Only run in low swell and light current because the ascent is a long open-water hang on the line.

As for Dee Why Wide but less tolerant: because bottom time is short and decompression margins thin, operators want under 1.5 m swell, minimal surface current and good visibility before committing to the deep edge. Winter and early spring give the clearest, calmest days; summer thermoclines make it noticeably cold at 35 m.

Descend the shot to the reef edge at 30 m, drop down the outer wall to the sand at 34–36 m and follow the base of the wall for 8–10 minutes looking under the overhangs, then come up onto the plateau at 26–28 m for the remainder before returning to the shot. Ascend with a deep stop at 15 m and an extended safety stop; DSMB if not on the line.

Nitrox 28–30% or planned light decompression; a 50% deco cylinder is common practice for teams pushing past 15 minutes.

Sydney Dive Charters – 'Dee Why Wide (Deep) 30–36 m' on request for Deep-certified divers; Pro Dive Manly – lists a 37 m maximum for its Dee Why Wide trips; otherwise private boats and technical clubs as a nitrox/light-deco reef dive.