The jetty at the northern end of Pirates Bay is the working heart of Eaglehawk Neck diving: the dive centre's catamaran and Go Dive Tasmania's seal-snorkel boat both leave from here. It is also a useful shore dive in its own right, especially for divers who want an easy first dive to check weighting and drysuit trim before the boat sites, or a night dive after a day on the water. The bottom slopes gently from the beach across sand and low reef to 8-12 m, with kelp and brown algae on the rocky sections.

The main attraction is weedy seadragons, which the dive centre notes can be found around the peninsula all year and which frequent kelp-edge habitat of the kind found here. Around the jetty and reef edge divers also find wrasse, leatherjackets, stingarees and rays on the sand, cuttlefish, octopus, sea stars and nudibranchs. Night dives are productive, with octopus and crabs out hunting and fish asleep in the weed.

Visibility is usually lower than on the outer coast, typically 5-15 m, because the bay is shallow and sandy. The dive is easy and forgiving, with no current and a clear reference in the jetty, and it suits beginners, photographers and anyone looking for a relaxed seadragon search. The main hazard is boat traffic: the ramp is busy with charter and private boats, so surface only along the edge of the reef away from the ramp and carry a dive flag.

The jetty sits at the edge of the historic Eaglehawk Neck, where convict-era guards once chained a line of dogs across the isthmus to stop escapes from Port Arthur, and there are cafes and accommodation within a few minutes' drive.

From Hobart drive the Tasman Highway to Sorell and the Arthur Highway through Dunalley to Eaglehawk Neck (about 75-80 km). Just before the Neck, turn east onto Pirates Bay Drive/Old Jetty Road and follow it down to the jetty and boat ramp at the northern end of Pirates Bay. There is parking beside the ramp; kit up at the car and walk a few metres to the water.

Keep well clear of the ramp itself and the jetty berths, where the dive and fishing charters load, and fly a dive flag.

Pirates Bay faces east-north-east into the Tasman Sea and is sheltered from westerly and south-westerly winds by the Forestier and Tasman peninsulas. North-easterly to easterly winds and swell send waves onto the beach and make the entry difficult and the water murky; in those conditions the site is best avoided. The northern corner by the jetty is the most protected part of the bay.

There is no significant tidal current. Visibility is best after a spell of westerlies; heavy rain reduces it for a day or two. Night dives are best on calm, moonless nights.

Enter beside the ramp, swim out along the jetty to 5-6 m, then follow the edge of the reef and kelp where seadragons feed. Keep the jetty on one side for navigation, turn at half air and return along the sand edge, surfacing well away from the ramp.

Eaglehawk Dive Centre – departure point for all its boat dives and used for training, seadragon and night dives; Go Dive Tasmania – seal snorkel and boat trips launch from Pirates Bay boat ramp.