Shark Alley is Hardy Reef's big-animal dive. 100 Magic Miles describes a steeply dropping wall to 20 m, with coral rubble below that depth, and lists white-tip and black-tip reef sharks, whalers, hammerheads and tiger sharks among its visitors. Depths range from 4 to 20 m and visibility is lower than at many outer-reef sites – 6–15 m – probably because of the water movement and suspended material in the tidal flow. Current is the defining feature, and the reason the sharks are there.

The guide warns that it is strong, especially at the bottom of the tide, and advises against snorkelling. This is a drift dive for experienced divers: drop in up-current, ride along the wall and let the boat collect you. The wall itself carries hard and soft coral on its upper sections, with fish sheltering in overhangs, while the rubble slope below 20 m is where reef sharks often rest or patrol.

The shark list is impressive, but divers should keep expectations reasonable: white-tips, black-tips and grey whalers are the regulars, and hammerheads and tigers are occasional sightings. As with any shark site, divers should stay calm, stay together and not chase animals. No day-trip operator lists Shark Alley, and it is likely to be visited only on liveaboard or private charters with skippers familiar with the tides.

It should not be confused with Shark Alley on Wheeler Reef off Townsville. Given the conditions, it is suited to Advanced divers with drift experience and SMBs. Photographers should expect to shoot on the move, and anyone uneasy about sharks will find the nearby Reefworld wall a gentler introduction to Hardy Reef.

Boat only. Hardy Reef lies on the outer Great Barrier Reef roughly 80 km offshore from Airlie Beach and Hamilton Island. Cruise Whitsundays' high-speed catamarans depart Port of Airlie (Airlie Beach) daily, with connections from Hamilton Island and Daydream Island, and reach the Reefworld pontoon in about 2 hours; scenic flights (about 30 minutes) also land at the reef by seaplane or helicopter.

Paid parking is available at Port of Airlie. Divers book certified or introductory dives on board. Other Hardy sites and the neighbouring Line, Sinker and Fairey reefs are reached by liveaboards and private charters; private vessels must use public moorings and observe no-anchoring areas.

Hardy and its neighbours are outer-shelf reefs fully exposed to the south-east trades (15–25 knots April–September). The large Reefworld catamarans run in most weather, but the crossing is rough in strong winds and diving can be restricted; smaller charter boats need a settled forecast. Hardy Reef's lagoon drains through a deep channel (about 60 m) beside the pontoon, and strong tidal currents run along the reef edges and through the gaps between Hardy, Line, Sinker and Fairey reefs, especially on spring tides and at the bottom of the tide – plan edge and wall dives for slack water.

Visibility is typically 8–20 m, up to 30 m on the outer faces. Marine stinger season (box jellyfish and Irukandji) runs roughly November to May – wear a full-length stinger suit or wetsuit with hood and gloves, carry vinegar. Cyclone season November–April; tropical lows and cyclones can close sites and damage coral (TC Yasi 2011, TC Debbie 2017).

Current at Shark Alley is strong, especially at the bottom of the tide.

Drop in up-current at slack water, descend the wall to 15–20 m and drift with the reef on one shoulder, watching the rubble slope and blue water for sharks; deploy an SMB and ascend along the wall for live-boat pick-up.

No regular day-trip operator; visited on liveaboard/overnight dive trips from Airlie Beach and private charters. Cruise Whitsundays' Reefworld is nearby on Hardy Reef.