Gates Bluff Bay is the easy shallow site of the Schouten Island group, rated 6 out of 10 by the Marine Life Network guide as a sheltered bay with thick weed in 5-10 m, suited to a second-tank dive. The guide notes that clean ocean currents keep the water clear.

The weed garden supports wrasse, leatherjackets, southern hulafish (Trachinops) and banded morwong, and abalone and crayfish shelter under the ledges. It is the kind of dive where slow, careful searching of the weed turns up small animals, and it is also good snorkelling.

It suits all levels in a self-sufficient boat party and is a comfortable place to finish a Schouten Island day.

Schouten Island is part of Freycinet National Park. Its granite and dolerite peaks rise to over 400 m, and the island has no permanent residents, jetty or facilities apart from a Parks hut and campsite at Moreys Bay, so divers visit with self-contained boats. The island's sites were described in detail in the Marine Life Network regional guide, but few have been documented since; with no operator currently running trips, they are among the least-dived good sites in Tasmania.

A typical Schouten day combines one deeper dive on the exposed eastern or southern side with a shallow second dive in a sheltered bay, choosing sides according to the swell. Because the island is at least 45 minutes from the Coles Bay ramp and more than four hours by road and boat from the Royal Hobart Hospital chamber, conservative profiles, oxygen on board and a reliable weather window are essential.

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. Schouten Island lies across Schouten Passage from the southern tip of the Freycinet Peninsula, roughly 25-30 km (about 45-60 minutes in a fast boat) from the Coles Bay ramp via Promise Bay and the western shore of the peninsula.

Swansea's ramp on the western side of Great Oyster Bay is an alternative. Schouten Passage can run hard with wind against tide. Gates Bluff Bay is on the sheltered side of the island and serves as an anchorage for a second dive.

Gates Bluff Bay is sheltered and suitable as a second dive in most conditions that allow the crossing to Schouten Island; strong westerlies may reach it across Great Oyster Bay. Clean ocean currents keep visibility good. 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.

Anchor in the bay and dive the weed-covered reef at 5-10 m, following the shoreline in one direction and returning. Ideal for a relaxed second dive or snorkel. Turn the dive at half gas (thirds where current or overhead sections are involved), deploy an SMB before surfacing for the live-boat pick-up, and complete a 3-minute safety stop at about 5 m where depth allows.

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.