Low Head, at the entrance to the Tamar River, is home to Australia's oldest continuously operating pilot station (1805) and a lighthouse, and the foreshore below them is the most accessible dive at the Tamar heads. The Marine Life Network guide rates the shore dive 6 out of 10: a flat terrace reef in 2-6 m with good parking and museum access, and a moderate current that can be used for a drift.

Fish include barber perch, weedfish, zebrafish, wrasse, magpie perch and sea sweep, with small, stunted abalone and patches of Macrocystis kelp on the western side. Tasmanian Divers in Launceston advertise giant kelp forests and sponge gardens among the northern sites they dive. As with all Tamar entrance sites, local knowledge of the tides is worth more than any written description, and a first visit with Launceston club divers is the best introduction.

The Tamar entrance is one of the most tidally energetic dive areas in Tasmania, and the Marine Life Network guide classes several sites here as category 4-5 because of current and shipping. Hebe Reef, a shallow reef at the mouth, has claimed many ships since the early 19th century, and its wrecks are protected historic sites. The flip side of the current is prolific filter-feeding life - sponges, bryozoans and ascidians - on any structure the water flows over.

Launceston divers have access to these sites within an hour of the city, and the sheltered Low Head shore dive is a regular training and club venue. The nearest hyperbaric chamber, however, is at the Royal Hobart Hospital about 3 hours' drive south, as Launceston General Hospital has none, so plan slack-water dives conservatively.

Low Head is at the eastern side of the Tamar River mouth, 5 km north of George Town and about 55 minutes (55 km) north of Launceston via the East Tamar Highway (A8). Boats launch at the Low Head, George Town or Kelso ramps. The Tamar is a commercial port (Bell Bay), so contact Port Control on VHF and keep out of the shipping channel when ships are moving.

Drive to the Low Head pilot station or lighthouse car park at the end of Low Head Road; there is good parking and a short walk (under 100 m) to rocky entry points. Enter on the sheltered side according to the tide - the reef can be used as a gentle drift with the current.

The Tamar heads are dominated by tide: large volumes of water flood and ebb through the entrance, and most boat sites can only be dived at slack water, typically within about an hour of the turn. North-westerly to north-easterly winds blow straight into the entrance and, against an ebb tide, create steep breaking seas over the bar and Hebe Reef. Southerly winds blow offshore and give the calmest water.

Visibility is best on the flood tide, when clear Bass Strait water enters; the ebb brings turbid river water, especially after rain. The shore dive is diveable more often than the boat sites; enter near slack or plan a drift with the tide.

Enter near slack, follow the flat terrace reef at 3-6 m, and either return to the entry or drift with the tide to a pre-agreed exit. The Macrocystis kelp is on the western side. Turn at a third of gas to allow for the swim back and a possibly harder exit, finish with a 3-minute safety stop at about 5 m if the depth allows, and exit where you entered unless an alternative exit has been checked beforehand.

Tasmanian Divers (42 Invermay Road, Launceston) runs regular local dives at northern shore sites including the Tamar region; Launceston clubs (Tas Uni Dive Club Northern Chapter and others) dive Low Head and the Tamar heads. No charter boat is based at Low Head; boat sites are dived from private boats launched at Low Head, George Town or Kelso.