Sleepy Bay is the most accessible shore dive on the ocean side of the Freycinet Peninsula, a small cove below the Cape Tourville road that is more often visited for its lookout than its diving. The Marine Life Network guide rates it 6 out of 10 and describes a rocky reef and sand bottom from 2 to 12 m, sheltered from easterly swell, with granite bommies in 10-12 m, one of which is undercut to form a large cavern, and long, low reefs across the sand.

The life is typical of the east coast granite reefs: wrasse, leatherjackets, banded morwong and bullseyes, with sponges, yellow zoanthids and tube worms on the rock and abalone and crayfish in the cracks. Conger eels are recorded in the bommie cavern. The guide notes that the kelp forest that once grew here had recently disappeared, and like much of the east coast the giant kelp has not returned in its former density.

The appeal of Sleepy Bay is its setting. The orange-lichen granite of the Hazards and the clear water of the peninsula make it a beautiful place to dive, and it is almost always quiet. The trade-off is the access: the path down is short but steep, and the climb out with a cylinder on your back is the hardest part of the dive.

It suits fit Open Water divers who are self-sufficient, as there is no dive shop or air on the peninsula. Snorkellers can enjoy the shallow reef around the cove on calm days. With no published GPS mark, divers should follow the cove's southern shoreline out to find the bommies.

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. From Coles Bay drive into Freycinet National Park (Parks Pass required) and take the unsealed Cape Tourville road; the Sleepy Bay car park and lookout are signposted about 6 km from the park entrance.

A steep walking track of roughly 10 minutes leads down to the cove; carrying scuba gear down is manageable but the climb back up after the dive is hard work, so take gear down in two trips if needed.

Sleepy Bay faces south-east but is tucked in behind the headland, and the Marine Life Network guide describes it as sheltered from easterly swell. A big south-easterly or southerly swell makes the cove surgy and entry dangerous, while westerly winds blow offshore and flatten it. Visibility can be low after long spells of onshore weather.

Summer afternoon north-easterlies do not affect it much.

Enter from the cove, swim out along the reef to the granite bommies in 10-12 m, circle the undercut bommie with its cavern and follow the long low reefs across the sand before returning along the rocks. Save energy for the steep walk out.

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.