Fosters Island, off Cape Portland, is rated 6 out of 10 by the Marine Life Network guide. The island has a shallow weed garden in 2-6 m with good fish life, crayfish and large abalone, and the remains of two small historic wrecks, the Memento (1877) and the SS Athletic (1881). The guide warns of dangerous tidal rips in the passage and advises avoiding strong opposing wind and tide.

The larger General Picton and Loch Finlas wrecks lie nearby, so Fosters Island makes a shallow second dive on a wreck-diving day in this corner of the state. Treat the depths, positions and conditions given here as a starting point, and confirm them with local divers and a depth sounder before committing to a dive.

The far north-east corner of Tasmania, from Eddystone Point to Cape Portland and Swan Island, is one of the most remote stretches of the state's coast. Roads north of St Helens and around Gladstone are partly gravel, the nearest shops are at Gladstone, Derby or Bridport, and there are no dive services at all. The Marine Life Network guide, written from the experience of Launceston divers, is still the only detailed published account of most of these sites.

Where Bass Strait meets the Tasman Sea around Cape Portland and the Swan Island group, tidal streams run hard, and the guide repeatedly stresses slack water, safety lines and experienced boat handlers for the wreck sites. The Royal Hobart Hospital chamber is five hours or more away by road, so any diving here should be conservative and planned with an evacuation route in mind.

Launch at the Little Musselroe River or Musselroe Bay and run west to Fosters Island, about 25 minutes. Dangerous tidal rips run through the passage; approach on the east side on a rising tide. There are no marinas or fuel on this coast apart from the towns named, so carry spare fuel, a VHF radio and an EPIRB, leave a trip plan ashore, and check MAST boating advice; many north-coast ramps are shallow at low tide, and a 4WD tow vehicle is a real advantage.

The Cape Portland and Swan Island area lies where Bass Strait meets the Tasman Sea: strong tidal streams run through the passages and between the islands, and wind against tide creates steep, dangerous seas. Diving is only practical at slack water in light winds; westerly swell and strong easterlies both make the area unworkable. Avoid strong opposing wind and tide; the east side on a rising tide is preferred.

Use the Bureau of Meteorology coastal forecast for the North East Coast and Banks Strait, and check tide times for the nearest standard port before planning the run.

Drop on the east side at slack or on the rising tide and explore the weed garden at 2-6 m, looking for the scattered remains of the two small wrecks. Turn the dive at half gas (thirds where current or overhead sections are involved), deploy an SMB before surfacing for the live-boat pick-up, and complete a 3-minute safety stop at about 5 m where depth allows.

No commercial operator. Dived occasionally by Launceston clubs and Tasmanian Divers (Launceston) groups, and by private boats and cray divers. Remote - full self-sufficiency required.