The Bremer Canyon is not a dive site, but it is included here because divers visiting Bremer Bay invariably ask about it. The canyon is part of a system of submarine canyons incising the continental shelf edge off the south coast, where upwelling of nutrient-rich deep water drives a rich food chain. Every summer, from about December to April, it hosts one of the largest known aggregations of killer whales in the southern hemisphere – often dozens of animals in multiple pods – feeding on beaked whales, squid and other prey.

Expeditions run from the Bremer Bay Boat Harbour, travelling about 90 minutes offshore for an 8-hour day. Naturaliste Charters reports a sighting rate of around 96% in season, and also regularly records sperm whales, long-finned pilot whales, beaked whales, pygmy blue whales, striped and bottlenose dolphins, sunfish, and great white, oceanic blue and whaler sharks, along with albatrosses and other seabirds. Predation events on beaked whales have been documented on film and have made the site internationally known.

No operator offers swimming or diving with the orcas, and the canyon's depth (hundreds of metres), remoteness, currents, the presence of large sharks and the nature of the predation make it unsuitable for in-water activity. Commonwealth marine mammal regulations also limit approach distances.

For divers, a Bremer Canyon day makes an excellent complement to the seadragon shore diving in Bremer Bay itself – plan several days in town to allow for weather, and book the canyon trip early in the season.

Bremer Bay is about 180 km (2 hours) north-east of Albany and 500 km (5-6 hours) south-east of Perth via the Albany Highway and Borden-Bremer Bay Road, or via the South Coast Highway and Bremer Bay Road. Air fills, hire gear and guided dives are available from Bremer Bay Dive in town. Orca expeditions depart the Bremer Bay Boat Harbour at about 8 am (check-in 7:45) for an 8-hour trip, running roughly 90 minutes offshore to the canyon.

Naturaliste Charters runs daily trips from December to April aboard the Alison Maree; Geographe Maritime Charters and others also run canyon trips.

The canyon is on the open continental shelf edge of the Southern Ocean, fully exposed to swell and wind from all directions. Trips go ahead only in suitable weather and are frequently rescheduled; summer high-pressure systems with easterly winds are typical, and seas of 1.5-2.5 m are common. Seasickness is a real consideration on the 90-minute crossing.

Not applicable – there is no recreational diving at the Bremer Canyon. Wildlife is viewed from the vessel.

Not a dive site. Commonwealth marine mammal approach regulations apply.

Naturaliste Charters – daily orca expeditions December-April (96% sighting rate claimed); Geographe Maritime Charters – Bremer Canyon killer whale expeditions. No operator offers diving or in-water encounters.