The Isolated Reefs are two oval outcrops sitting alone on the sand north-west of the main Bare Island reef, and for many regulars they are the best part of the site. Isolated Reef One runs west-north-west, is 60–70 m long and 30–35 m wide, with walls on its northern side reaching 18–19 m; Isolated Reef Two, 20–30 m further on, is larger and deeper, mostly at 19 m on the sand at high tide, and is cut by cracks, holes, bays and rocky outcrops. Both are smothered in sponges, sea squirts and gorgonians, and both are littered with the debris of a century of fishing boats – anchors, rope and chain, fibreglass hull sections, old Admiralty anchors and metal objects.

The fish and critter life is rich: kingfish schools sweep through, seapike, sweep, trevally, yellowtail and one-spot pullers hang over the reefs, luderick and old wives shelter in the bays, flathead up to 1.25 m lie on the sand, and the reefs are reliable for big-belly seahorses, red Indianfish and painted anglerfish. Weedy seadragons were once abundant here and are still seen, though less often since 2009. The dive is an exercise in navigation.

From the mainland platform west of the main car park it is an 8–10 minute compass swim over featureless sand to Reef One, and the La Perouse–Kurnell power cables deflect compasses nearby; from the island it is a longer swim along the Right reef. Current in the 16–19 m band on big tides can be strong and contrary. McFadyen recommends 30–35 minutes on the reefs, 45–60 minutes total, an 11–12 L tank and a safety stop because of the depth.

For advanced divers comfortable with navigation it is a quieter, clearer, deeper Bare Island with the same macro and more fish.

Bare Island is part of Kamay Botany Bay National Park, 20 km from the CBD. Drive down Anzac Parade to the La Perouse loop and park on the edge of Anzac Parade as close to the island's access road as possible (arrive before 8 am on weekends). Gear up at the car, walk 200 m down the access road and across the timber footbridge to the island, then down the stairs to the rock platform.

Island entries (boat ramp, western point or Pool) involve a 10–20 minute swim west along the Right reef to the Isolated Reefs. The shorter mainland option: park in the right-angle car park west of the main Bare Island parking, overlooking the grassy flat; walk down to the rock platform, enter, descend at 5 m and navigate south or south-west across the sand for 8–10 minutes to Reef One. Return the same way; 11–12 L tank recommended.

Sheltered like the rest of Bare Island and diveable in most seas, but strong currents run through the 16–19 m zone on big tide differences and often in unexpected directions – dive at or near high tide when clarity is also best. Visibility here is generally better than on the main reef but ranges from 2 to 25 m. The electricity cables from La Perouse to Kurnell deflect compasses near the reefs, so trust your surroundings as much as the needle.

Boats cross the sand between the reefs and the mainland; a long swim back is the price of surfacing early.

From the mainland entry descend at 5 m and swim south-west over sand to 10–11 m; Reef One appears after 8–10 minutes. Circle it keeping it on your left along the northern (deeper) side, cross 20–30 m of sand to Reef Two, explore its cracks, holes and bays, and return via the southern edges – 30–35 minutes on the reefs, 45–60 minutes total, with a safety stop over the sand edge.

Abyss Scuba Diving, Sydney Dive Academy and Pro Dive guide it as an advanced navigation dive; experienced independents.