Hardy Reef South is the reef's southern face, which 100 Magic Miles describes as a steep slope dropping from 3 to 30 m, with hard and soft corals and 'numerous deep gullies'. Depths range from 5 to 30 m and visibility is often excellent, 12–30 m, because the site faces open water. The structure resembles Bait Reef's Southern Face: gullies run down the slope, sheltering angelfish, sweetlips, cod and wrasse, while mackerel, trevally and barracuda patrol the open water.

Soft corals grow on the current-swept edges of the gullies and hard corals dominate the shallows. For photographers, clear water and dramatic gully walls make good subjects. Current can be strong, the guide warns, and snorkelling is not recommended.

The south face also takes the south-east swell, so it is diveable only in calm conditions. This makes it a site for experienced divers, best done as a drift with an SMB and a live boat. No day operator lists Hardy Reef South by name.

Cruise Whitsundays' Reefworld pontoon is on another part of Hardy Reef, and its guided dives stay near the pontoon wall. The south face is most likely to be dived from liveaboards or private charters. Its coral condition since Cyclone Debbie and subsequent bleaching events has not been documented in the sources reviewed.

On a calm day with clear water it would rank among the better wall-and-gully dives of the Whitsunday outer reef. A sensible plan is to dive it early in a charter's stay at Hardy, while conditions are known to be calm, and keep the pontoon wall or the Canyons as fallbacks if the swell rises.

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).

The southern face is exposed to south-easterly swell.

Descend the slope to 20–25 m, drift along the face exploring the deep gullies, then work up to the hard-coral shallows at 5 m for the second half of the dive. SMB for 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.