Blubber Head marks the northern entrance of Port Esperance, the bay on which the town of Dover stands in Tasmania's far south; its name recalls the whaling era, when whale blubber was rendered at stations around these bays. The Marine Life Network guide describes a steep underwater slope dominated by large boulders in 5-10 m, a large variety of leatherjacket species including toothbrush and horseshoe leatherjackets, and a range of reef fishes. It notes that the site is regularly dived and potted, and that it is unsafe in strong southerly weather.

The boulders create a three-dimensional reef with gaps and overhangs, covered in kelp and brown algae on top and encrusting sponges and ascidians on shaded faces. Leatherjackets are the stars: the horseshoe leatherjacket, with its striking yellow horseshoe marking, and the toothbrush leatherjacket, named for the bristles near its tail, are among several species present. Wrasse, magpie morwong, bastard trumpeter and rock lobster are also common.

The site is easy, shallow and close to Dover's boat ramp, making it a good introductory boat dive in the far south. Watch for cray pot lines, as the guide notes the area is potted. Dover has accommodation, a store and fuel, and makes a good base for exploring the far-south sites, including the Katherine Sharer wreck and Lomas Point in Port Esperance.

The far south has no dive shop, so bring filled cylinders from Hobart or Kingston, and allow for patchy mobile coverage by carrying a VHF radio and leaving a trip plan.

Dover is on the Huon Highway about 85 km (1 hour 20 minutes) south of Hobart via Huonville and Geeveston. There are boat ramps and jetties at Dover and around Port Esperance. The Marine Life Network guide lists Blubber Head as a boat dive from Dover; it lies at the northern end of Port Esperance, a short run (5-10 minutes) from the Dover ramp.

Anchor in sand off the boulder slope.

The far south – Port Esperance, Southport and Recherche Bay – opens southward to the Southern Ocean. Southerly and south-westerly swell and strong southerly winds make the exposed sites unworkable and quickly reduce visibility, while northerly and light westerly winds give calm water. Sheltered bays such as Port Esperance and inner Recherche Bay remain diveable in moderate conditions.

Weather changes rapidly and fronts arrive every few days; plan around high-pressure systems in late summer and autumn and watch for south-westerly changes. The Marine Life Network notes Blubber Head is unsafe in strong southerly weather.

Descend on the boulder slope at 8-10 m, zig-zag up and down through the boulders looking for leatherjackets and invertebrates, and finish in the shallows at 5 m.

No regular operator; private boats and club expeditions. Underwater Adventures Tasmania runs occasional far-south trips (the Acteons are mentioned by Go Dive Tasmania as a kelp-diving area).