Remark and Frederick Islands offer some of the best-documented deep reef diving in the Recherche Archipelago. Marine Life Network describes Remark Island's sheltered northern side as shallower, with blue groper, morwong, boarfish, harlequin fish, western blue devils, silver drummer, yellowtail, bullseyes and seals, while its exposed southern side drops into 50 m with sponges, gorgonians, soft corals and black coral. Frederick Island, just east of Remark, is a large granite dome rising from 40 m, with depths of 20-40 m and similar marine life.

The contrast between the two sides of Remark makes it versatile. On the north, relaxed dives along granite boulders suit Advanced Open Water divers and allow time with the resident seals and big fish. On the south, the wall plunges through sponge and gorgonian gardens into black coral territory, a rare sight in recreational depths and a sign of the site's pristine condition.

Frederick Island's dome is a different experience: smooth granite rising from the depths, with fish concentrated around its flanks and top. It is best dived in flat conditions with a live boat.

These islands are a long way from Esperance and dived infrequently, so fish are abundant and relatively unafraid. They suit experienced divers visiting on a multi-day Esperance trip, ideally with nitrox and conservative profiles given the remoteness.

The Recherche was named in 1792 by the French admiral Bruni d'Entrecasteaux after his ship Recherche, while Esperance takes its name from his second vessel, Espérance. The archipelago's reserve status protects the islands, but the waters are not a no-take marine park, so crayfish and fish numbers vary with fishing pressure; the remoteness of islands such as Remark and Frederick keeps them among the richest.

Esperance is about 720 km (8 hours) south-east of Perth via the Albany or Great Eastern and Coolgardie-Esperance Highways, with daily flights from Perth. Dive boats and private boats launch from the Bandy Creek Boat Harbour (5 km east of town, with ramps, parking and toilets) or operate from the town waterfront on The Esplanade. Air, nitrox and hire gear are available from Esperance Diving & Fishing on The Esplanade.

Remark and Frederick Islands lie in the eastern part of the inner archipelago; allow roughly 60-75 minutes by boat from Esperance. Operators anchor on Remark's sheltered northern side, or drift the southern drop-off with a live boat in calm conditions.

The Recherche Archipelago lies open to the Southern Ocean, and the islands shelter each other only partly. Boat diving needs swell under about 2 m and winds under 15-20 knots; the prevailing south-westerly swell and winter cold fronts cancel many trips from May to September. Summer brings reliable morning calms but strong easterly sea breezes most afternoons.

Remark Island's northern side is sheltered from south-westerly swell and suits most calm-to-moderate days; the southern face, where the wall drops to 50 m, and Frederick Island's dome are exposed and need near-flat seas.

On the north side of Remark, descend to 12-20 m and cruise the granite with its fish and seals. On calm days, drop on the south side and descend the wall to a planned depth (30 m recreational), then ascend along the face. At Frederick Island, circle the dome from 30 m upwards.

South wall beyond 40 m requires deep/technical training; nitrox recommended for repetitive dives.

Esperance Diving & Fishing (72 The Esplanade, Esperance; operating since 1983) – boat dives in the Recherche Archipelago on demand/weather permitting, minimum numbers apply for long trips – on longer island days in good weather.