Manly Cove is the beach beside the ferry wharf, and the dive is along and around the netted swimming enclosure on its western side, in front of the building that was Oceanworld and then Manly Sea Life Sanctuary until it closed in 2018. It is 2–6 m deep, flat, sheltered and full of small animals, and Dive Centre Manly runs more dives here than anywhere except Shelly Beach. The bottom is sand and seagrass with scattered rocks and the pylons and nets of the enclosure, and it is those nets that matter: White's seahorse, Sydney's endangered endemic, colonises the mesh in numbers, and the cove has been part of the Sydney Institute of Marine Science's 'seahorse hotel' recovery program.

Pro Dive lists the site as 'Manly Nets' at 2 m depth, noting the seahorses along the nets and the very long bottom times the depth allows. Around the seahorses is a proper muck-dive cast: striped and yellow anglerfish on the pylons, pipefish and pygmy pipehorses in the weed, cuttlefish and squid at night, octopus in bottles and cans, stingarees and small stingrays on the sand, fan-bellied leatherjackets, and in autumn juvenile tropical fish sheltering along the seawall. Little penguins from the North Head colony sometimes fish through the cove at dusk.

This is not a site for scenery or depth; it is a site for looking closely, and it works as a first dive, a Discover Scuba, a night dive or a macro-photography session between ferries. Ferry wash and the summer swimming crowds are the only complications, and the net line keeps divers out of the boat lane. Manly Cove suits absolute beginners, snorkellers and seahorse hunters, and it is the reason Manly can promise a seahorse to almost anyone who asks.

Manly Cove West is the beach immediately west of Manly Wharf on West Esplanade, 200 m from the ferry (20 minutes from Circular Quay) – the easiest public-transport dive in Australia. By car, West Esplanade and the Manly Wharf/Whistler Street car parks are paid and busy; Dive Centre Manly in Belgrave Street is a five-minute walk with a trolley. Gear up on the promenade or grass, walk down the steps onto the sand and wade in beside the netted swimming enclosure.

Most of the dive is along the outside of the net and around its pylons toward the old aquarium building. Exit back onto the same beach.

Almost completely sheltered: Manly Cove faces south-west into North Harbour and is protected by the peninsula from swell and from the north-easter; only a strong southerly wind puts chop on the beach. The limits are visibility and traffic. Visibility is 3–8 m, best on the flood tide and on winter westerlies, and poor for days after rain when stormwater enters the cove.

Ferries, the fast ferry and tourist boats use the wharf 200 m away and their wash reaches the beach; stay inside or beside the net line. Summer weekends bring crowds of swimmers to the enclosure; early mornings and nights are best.

Enter beside the net, descend to 2–3 m and follow the outside of the swimming enclosure net slowly, checking each panel and pylon for White's seahorses, then continue west over the seagrass and sand toward the old aquarium seawall at 4–6 m looking for anglerfish, pipefish, cuttlefish and rays. Return along the inside or outside of the net. Sixty minutes on a single cylinder is normal; at night stay within the enclosure area.

Dive Centre Manly – guided shore dives, Discover Scuba, Open Water confined-water dives and night dives here several times a week; Pro Dive Manly – 'Manly Nets' (2 m, seahorses) guided dives; Sydney Dive Charters shore-dive option with Manly Wharf pick-up.