Lemon Rock is a granite islet at the mouth of Wineglass Bay and one of the more remote dives on the east coast. The Marine Life Network guide rates it 6 out of 10 and describes a weedy shelf that drops rapidly into 30-40 m, with bull kelp and cray weed in the shallows and clouds of butterfly perch on the deeper face.

The guide notes that the rock supports delicate marine life, including sea daisies and other invertebrates, and that crayfish are present. A slight current runs past the rock, which helps the filter feeders, and schools of fish and marine mammals - seals and dolphins - are possible. The granite here is the same as the rest of the Freycinet coast, so expect boulders, vertical faces and cracks rather than ledges.

Lemon Rock is best thought of as an expedition dive. It is well away from any ramp, there is no dive operator on the peninsula, and the rock is exposed to the open Tasman Sea. The reward is a genuinely rarely dived site with clear oceanic water and a steep wall. It pairs with a shallow second dive or snorkel in Wineglass Bay itself.

It suits experienced, self-sufficient divers with a capable boat and skipper, deep training and an understanding that help is a long way off: the nearest chamber is in Hobart, several hours away. Documentation is limited to one regional guide, so divers should expect to explore.

Some context helps set expectations for all Freycinet diving. The peninsula's pink granite continues under water as rounded boulders, cracks and steep faces, and the area sits where the warm East Australian Current meets cooler southern water, so species lists mix typical Tasmanian fish with more northern visitors. Over recent decades warming water and grazing by the long-spined sea urchin, which has spread south from New South Wales, have thinned kelp beds along the east coast, and descriptions written in the 1990s may not match what you find today.

Coles Bay is 30 minutes south of the Tasman Highway via the C302 (turn off 12 km south of Bicheno), about 2 hr 45 min from Hobart and 2 hr 30 min from Launceston. The main public boat ramp is at Coles Bay township; boats reaching the ocean side of the peninsula or Schouten Island need a seaworthy vessel, as the run around Cape Degerando or through Schouten Passage is exposed. Lemon Rock is at the entrance to Wineglass Bay on the ocean side of the peninsula.

From Coles Bay the run is around Cape Degerando and down the ocean coast, or from Bicheno south past Cape Tourville - allow about an hour each way in a fast boat, and only attempt it in a settled forecast.

Lemon Rock is fully exposed to easterly and south-easterly swell and to the NE sea breeze; it can only be dived in westerly or light winds with swell under about 1.5 m. The long boat run means the whole trip depends on a stable forecast. Winter westerlies often give the best combination of flat seas and clear water.

Rain washes tannin-stained runoff into Great Oyster Bay, and summer afternoons commonly bring a fresh north-easterly sea breeze, so plan dives for the morning.

Descend on the lee side of the rock onto the weedy shelf, then drop down the face to your planned depth (25-30 m is enough). Swim along the face, returning up the wall to the shelf for a long safety stop in the kelp. Watch for the slight current.

No dedicated dive operator at Coles Bay or Freycinet. Sites are dived from private boats and occasional club expeditions (Tas Uni Dive Club, TSDC, Launceston clubs); the Marine Life Network guide notes that Coles Bay is the usual starting point for Schouten Island charters. Cruise and kayak operators in Coles Bay do not offer scuba.