North Curl Curl is the only rock-platform shore dive of any substance between Freshwater and Long Reef, and it belongs to the small band of Northern Beaches divers who watch the swell charts. The headland at the northern end of the beach carries the North Curl Curl rock pool and, beyond it, a broad platform from which divers stride into deep water. Below, the reef falls away as boulders and ledges with overhangs, crevices and swim-throughs, running from the shallows to a sand line at 18–20 m; the VIZ club's survey of the Dee Why–Curl Curl reef records that its northern third is shallow (8–12 m) and uninteresting, and that the reef becomes more varied, with increasing sponge cover, toward the southern and easternmost section – which is the part reached from Curl Curl.

The marine life is typical of exposed Northern Beaches reef: Port Jackson sharks in winter, wobbegongs, eastern blue devilfish in the darker overhangs, schools of yellowtail and sweep over the boulders, blue groper, red morwong, cuttlefish, octopus and nudibranchs, with kingfish and salmon passing along the wall and eagle rays over the sand. Sponges, sea tulips and bryozoans coat the deeper ledges. It is not Freshwater's equal for sea dragons but has more structure at depth.

The whole reef from Dee Why to Curl Curl is 1–2 km long and has been traversed by scooter divers and by boat, but from shore the practical dive is the southern end within a few hundred metres of the platform. It is an Advanced dive for the entry alone: significant surge on the platform in anything over a metre, a documented rip at the northern end of the beach, an exposed exit, and boats that come close to the headland. On a flat winter morning with 15 m visibility it is a fine, uncrowded reef; it suits experienced independent divers, scooter divers and photographers who have exhausted Cabbage Tree Bay.

From Pittwater Road turn east into Howard Avenue (Dee Why) and follow it to the free North Curl Curl Beach car park behind the surf club, which is congested on weekends. Walk 150–250 m north along the path past the North Curl Curl rock pool onto the headland rock platform. Gear up on the platform, watch the sets, and giant-stride into deep water off the northern edge during a lull.

The main reef lies south-east and east of the platform to a sand line at 18–20 m. Exit at the same platform between sets on the top half of the tide, or swim back around onto the beach through the shore break if the platform is awash. The northern (Dee Why) third of the reef is a long swim and is usually done by scooter or boat.

Fully exposed to north through east swell and only marginally protected from the south by the headland. Surge on the entry platform is significant in anything over 1 m, and the outer reef wall needs careful buoyancy in surge. Choose a morning with swell under 1 m and a westerly; the north-eastern sea breeze makes the afternoon exit dangerous.

A documented rip runs off the northern end of the beach. Tide: enter and exit on the top half so the platform edge is covered. Visibility 10–15 m on good winter days, 5 m after rain from Dee Why Lagoon or north-easterlies.

Carry a DSMB and, for the long reef traverse, a PLB.

Enter off the northern platform and descend to 8–10 m on the boulder slope. Work east and south-east along the reef through the overhangs and swim-throughs to the sand line at 18–20 m in the south-eastern corner where the sponge growth is best, turn at half air, and come back shallower at 10–12 m along the top of the reef to the platform. Ascend in the lee of the headland and exit during a lull; if the platform is breaking, surface-swim around to the beach.

No operator runs it regularly; occasional Pro Dive Manly or club dives in ideal conditions. Mainly independent local divers, scooter divers and the VIZ club, which has GPS-mapped the Dee Why–Curl Curl reef.