Isle du Nord is a small island near the Darlington jetty, marked by a navigation light. The Marine Life Network guide rates it 6 out of 10: 6-12 m, a Macrocystis giant kelp garden, crayfish and the fish attracted to kelp. It adds that the kelp had recently disappeared because of warmer conditions.

That loss of giant kelp has continued across eastern Tasmania, where more than 90% of the original forests are estimated to have gone. Divers should therefore expect a rocky reef with smaller brown algae rather than the canopy described in older accounts. Inside the reserve, crayfish remain abundant.

Isle du Nord suits new divers and is a convenient dive for groups staying at Darlington with a small boat or kayaks. It also works as a sheltered alternative when north-easterly weather affects the Fossil Cliffs and the north-east corner of the island.

Maria Island is a national park with no permanent residents apart from rangers, and the Darlington settlement preserves convict-era buildings from 1825 onwards. The marine reserve along the island's northern and western shores has been no-take since 1991 and has been used for long-term studies of how protection affects rock lobster and fish numbers, so reef life inside it is noticeably richer than outside.

Maria Island's boat sites are rarely visited because there is no operator on the island and the eastern coast is a long way from the Triabunna ramp. Visitors with their own boats should carry oxygen and a radio, check the forecast for Mercury Passage as well as the open coast, and remember that the Royal Hobart Hospital chamber is roughly two hours away by road once back at Triabunna.

Triabunna, on the Tasman Highway 1 hr 15 min (85 km) north-east of Hobart, is the gateway. The Maria Island passenger ferry (Encounter Maria Island) runs several times daily from Triabunna to the Darlington jetty, about 16 km and roughly 30-45 minutes; it carries people and small amounts of luggage but not vehicles, and dive cylinders should be cleared with the operator first. Private boats launch at the Triabunna ramp (best), Saltworks Road ramp, or Orford (shallow bar at the Prosser River mouth - difficult at low tide).

Isle du Nord is a few hundred metres off Darlington, about 30 minutes by boat from Triabunna and minutes from the Darlington anchorage.

Maria Island's western and northern shores (Darlington, Fossil Cliffs, Painted Cliffs) are sheltered from easterly ocean swell but exposed to strong westerlies and north-westerlies blowing across Mercury Passage, which are common in winter and spring. The eastern side (Mistaken Cape, Bunker Bay) faces the open Tasman Sea and needs westerly weather and small swell. Southerly swell wraps around Cape Peron and the southern end.

Visibility drops after rain as runoff flows from the Prosser River into Mercury Passage. Sheltered from southerly and easterly swell; exposed to north-westerlies.

Drop near the navigation light and circle the island at 6-12 m, looking under the ledges for crayfish. 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 operator based on Maria Island. Hobart shops run occasional trips: Go Dive Tasmania has offered Ile des Phoques seal dives and filmed Troy D dives; Tasmanian Scuba Diving Club and Tas Uni Dive Club run club trips from Triabunna. Most diving is from private boats.