The Darwin Princess was a 23 m (75 ft) steel passenger ferry licensed to carry 200 people. Among other work she carried Telecom staff across the harbour to Mandorah for the Radio Australia transmitter site on the Cox Peninsula. Cyclone Tracy crossed Darwin in the early hours of 25 December 1974 with gusts estimated at over 200 km/h, destroying most of the city and killing 66 people, many of them at sea. More than 20 vessels sank or were driven ashore in and around the harbour, and several of those wrecks now form a second, much more intact wreck trail beside the 1942 sites. On Christmas Eve 1974 the ferry either put to sea or broke her moorings with only her skipper, Ray Curtain, aboard, and vanished. She remained lost until 2004, when a fisherman snagged an anchor on an obstruction near the recently found Booya. Divers from Coral Divers made the first dives and confirmed her identity from drawings, and the water police and the skipper's family were notified.

The wreck lies upside down in about 26 m. She appears to have hit the seabed on her side and slid around 10 m across the sand before settling, with the port side buried. The rudder is torn away, the propellers are wrapped in heavy rope, the bow cleat is bent down and there is a large dent in the port side, perhaps from a pylon or another vessel. The mast and handrails are gone and doors hang loose; plastic chairs and life jackets remain inside the hull, and a wide, chaotic debris field surrounds it, including a large concrete block. Visibility is often only a metre or two, and one team reported a single exploratory dive running to 2.5 hours including decompression. This is a dark, deep, entangling site that tells a hard story, and it is one for experienced wreck divers only.

Boat only. Charters and private boats usually leave from Cullen Bay Marina or the Cullen Bay public boat ramp (off Marina Boulevard, 5 minutes' drive from the CBD, with trailer parking), then run out into the harbour; the Stokes Hill / Frances Bay ramp by the Waterfront is the alternative. Run time on a calm neap morning is typically 15-30 minutes.

There is no permanent surface marker on most sites, so a GPS mark and a shot line are needed; plan the trip to arrive before high-water slack.

Tide is everything in Darwin Harbour: the spring range is 7-8 m and tidal streams run hard through the harbour, so diving is generally only possible on neap tides (range under about 3-4 m), timed to the slack at high water when clearer ocean water sits over the site. Spring tides bring strong currents and silt-laden water with near-zero visibility. The dry season (May-October) gives the most consistent conditions; the south-east trade winds can chop up exposed water in the afternoon, so mornings are best.

In the wet season (November-April) run-off from the rivers and creeks drops visibility, afternoon storms build quickly, and the harbour is in cyclone season; box jellyfish are present October-May.

Descend a shot placed on the sand beside the hull at slack. Circle the upturned hull, look at the rope-fouled propellers and missing rudder at the stern and the dented port side, then make a short loop into the debris field. At 26 m in 1-5 m visibility keep it short, stay in contact with your buddy, and ascend on the shot.

Deep for the conditions; Nitrox helps. Some teams dive it with decompression planned. Two torches and a line cutter recommended.

No regular operator. Dived occasionally by experienced local groups and Darwin Sub Aqua Club; commercial operators may run it on request for experienced divers on a very good neap.