The Betsey Island graveyard, west of Little Betsey Island at the mouth of the Derwent, is Hobart's ships' graveyard: from the 1930s to the 1980s obsolete vessels, barges and sections of the old floating bridge were towed here and scuttled in about 20-34 m. The Marine Life Network guide calls it a huge concentration of wreck dives very close to Hobart, with a pebble-and-mud bottom that stirs up easily, poor visibility after bad weather or decaying Storm Bay swell, and massive yellow and white jewel anemones and, at times, hordes of school fish on the wrecks. Alongside the ships, the graveyard holds a collection of barges and two sections of Hobart's old floating bridge.

The guide describes barges used by the Hobart Tug Company to carry paper from the Australian Newsprint Mills (ANM) plant at Boyer down the Derwent, scuttled in 1986 when road transport made them obsolete. They include Army-built barges from 1945 (about 100 ft), Hobart-built ANM barges from 1960 (74 ft) – ANM5 and ANM6 among the flattened wreckage – and Department of Construction barges HTL 1, 2 and 4. One lies near the Macquarie's bow and another about 50 m south-west towards the Swiftness.

About 100 m either side of the main wreck area, roughly level with the southern end of Big Betsey Island, lie two 580 ft (177 m) concrete sections of the floating bridge that crossed the Derwent before the Tasman Bridge opened in 1964. They are heavily encrusted in jewel anemones. Another section of the same bridge survives above water as the jetty at Alonnah on Bruny Island.

The bridge sections are large, enclosed pontoons; the guide warns that entering them is extremely dangerous and requires a torch, guideline and experience. For most divers the exterior is the dive: long walls of concrete glowing with anemones, with fish sheltering along the edges. The barges are low and flattened, and are best visited in combination with the Macquarie.

South Arm is about 35 km (40 minutes) south-east of Hobart: cross the Tasman Bridge, follow the South Arm Highway (B33) through Rokeby and Lauderdale to South Arm. The main boat ramp is at South Arm (Blessington Street/Harbour area) with trailer parking and toilets; Lauderdale (Doran's Road) is an alternative ramp further north. From South Arm the Betsey Island graveyard lies about 5-6 km south-east across the mouth of the Derwent, west of Little Betsey Island, roughly 15-20 minutes by boat.

The Marine Life Network guide recommends an echo sounder to locate the individual wrecks, which are low on the bottom; there are no public moorings, so anchor carefully in the pebble-mud bottom off the wreck and leave a boat attendant.

Betsey Island lies at the mouth of the Derwent where it meets Storm Bay, so decaying southerly swell and strong southerly or south-westerly winds make the ride rough and stir up the pebble-and-mud bottom. The Marine Life Network notes the graveyard is not renowned for visibility and recommends calm, dry weather and an ebb tide, when clearer water sits over the wrecks. After Derwent floods the water can be very dark.

Northerly and light westerly winds give the best conditions; late summer and autumn are most reliable. Expect 3-8 m visibility at best, often less.

Shot a bridge section or barge located on the sounder, explore the exterior and the anemone-covered surfaces, and return to the shot. Do not enter the bridge pontoons, which require a guideline and overhead training.

Interior of bridge pontoons is an overhead environment requiring guideline and redundant lights.

No scheduled operator trips; Hobart clubs (Tasmanian Scuba Diving Club and others) and private boats from South Arm and Lauderdale. The Dive Shop Hobart and Go Dive Tasmania can advise.