The RMS Quetta was an iron-hulled steamship built by William Denny and Brothers at Dumbarton in 1881 for the British India Steam Navigation Company's Queensland Royal Mail service – 115.8 m long and 3,484 tons, according to Wikipedia. On the night of 28 February 1890, bound from Brisbane to London via Torres Strait, she struck an uncharted rock in the Adolphus Channel near Albany Island. The rock split her plates from bow to engine room, and she sank in about three minutes.

Of 292 people aboard, about 134 died – one of Queensland's worst maritime disasters. Survival was starkly uneven: only 19% of saloon passengers survived compared with 86% of steerage passengers, many of whom were Torres Strait Islander and South Sea Islander crew and passengers able to swim. The Quetta Memorial Church on Thursday Island commemorates the disaster.

The wreck lies on its port side in about 18 m, largely intact and coral-encrusted, south of Adolphus Island. Scuba Diver Life describes rusted holds and rooms to explore and a significant gash from the sinking that creates a unique pathway through the vessel; Greatest Dive Sites gives a depth range of 10–24 m and notes parts are scattered and many artefacts have been moved to museums. The marine life is spectacular – Professional Dive Services compares it with the SS Yongala, with literally millions of fish.

Divers report massive groupers, Queensland groper, manta rays, thousands of sweetlips, barracuda, cod, trout, angelfish and sharks, fed by the current that sweeps the channel. That current is the site's defining challenge. It can exceed four knots, and divers must wait for slack water – usually a short window once a day – and be ready to jump in immediately.

Visibility is typically 5–15 m. The wreck is protected under the Underwater Cultural Heritage Act 2018. The Quetta suits experienced divers comfortable with strong currents and wreck diving.

It is one of Australia's great historic wreck dives, and one of the hardest to time.

Fly Cairns–Horn Island (daily Qantaslink/Regional Express services, about 1 hr 45 min); Horn Island airport links to Thursday Island by a 15–20 minute passenger ferry. There is no full-service dive shop in Torres Strait, so diving is arranged either on an expedition liveaboard (Mike Ball's Spoilsport ends or starts its November Northern Exposure trips at Horn Island Pier and has dived the Quetta; PDS's MV Kalinda has also finished trips there) or through local contacts and club divers on Thursday Island with a local boat. Bring all equipment; fills are limited and must be arranged in advance.

Torres Strait is a shallow, tide-dominated passage between the Coral Sea and the Arafura Sea, and the tides drive everything. Currents in channels such as the Adolphus, Prince of Wales and Endeavour channels regularly exceed 4 knots, and sites are only diveable for a short slack-water window – often once a day, and sometimes not at all on big spring tides. Plan around neap tides and consult local tide tables for the exact slack.

The south-east trades blow strongly from about April to November, raising steep wind-against-tide seas; the calmest period is the transition around November–December (when liveaboards visit), and the north-west monsoon season (December–April) brings storms, cyclone risk, stingers and reduced visibility from run-off. Visibility is variable, typically 5–15 m, and is best on the flood tide during neaps.

Dive only at slack water and be ready to enter the moment the tide turns. Descend the line to the hull (lying on its port side in about 18 m), tour the exterior and the large gash along the side, keeping to the lee of the hull, and return to the line well before slack ends. Ascend the line for the safety stop – do not surface away from the boat.

Slack-water dive planning is critical – use local tide tables and have a surface support boat live-boating; penetration (through the hull gash and holds) only with wreck training, line and lights; heritage-protected (UCH Act 2018) – no artefact removal.

Mike Ball Dive Expeditions – Spoilsport has included the Quetta (tide permitting) on Northern Exposure expeditions ending/starting at Horn Island; PDS MV Kalinda has dived it on Cairns–Horn Island trips; otherwise local club divers from Thursday Island with a local boat.