China Wall is one of the great walls of the Flinders Reefs. Marinelife.org.au places it on Boomerang Reef, near Flinders, and describes a wall dropping to 1,000 m with sharks, pelagic fish, sea whips, gorgonians and black coral trees, and gorgonian sea fans up to 4.5 m wide. It names Whaler Station and Cod Wall as related sites nearby.

The wall is sheer, falling from the reef edge into the deep, and it is the fans that make it special. Gorgonian fans of that size are among the largest in Australian waters, spreading across the current like giant nets. Black coral trees and sea whips add to the forest on the face, and soft corals grow in between. Visibility in the Flinders area frequently exceeds 40 m, so the scale of the wall and its fans can be appreciated fully.

Sharks patrol the drop-off, including grey reef, whitetip and silvertip, and pelagic fish such as trevally, barracuda and tuna pass along the wall. Cruising the Edge reports tiger sharks and tawny nurse sharks in the Flinders area. Smaller animals include anthias, butterflyfish, angelfish and hawkfish perched on the fans.

China Wall suits advanced divers comfortable on a deep wall with nothing beneath them. The biggest fans lie toward the deeper end of recreational range, so depth and gas need careful management. Precise location and depth range are not published, and the name does not appear on current operator itinerary pages, so the site may be dived under another name or only occasionally.

Liveaboard only, from Townsville. Mike Ball's Spoilsport visits Flinders on its 7-night Yongala & Coral Sea expedition (depart Breakwater Marina, Townsville, Thursday evening, finish in Cairns) and the 10-night Coral Sea Odyssey; the overnight crossing is about 140 nautical miles (260 km), passing Myrmidon Reef on the outer Great Barrier Reef. Private expedition yachts anchor behind the main sand cay in about 30 m over sand.

China Wall is dived from a mooring or tender drop along the wall, when conditions allow.

The Flinders Reefs lie about 250 km off the Queensland coast, roughly 140 nautical miles north-east of Townsville, beyond the outer Great Barrier Reef. The crossing is made overnight through open ocean and is uncomfortable in SE trades over about 20 knots (common June–August). The main sand cay gives some shelter from the trades, and the lagoon pinnacles are more protected than the outer walls.

Currents can be strong through the reef gaps and over the mid-reef bommies. September–December usually gives the calmest seas and 40 m-plus visibility; December–April is cyclone season.

Descend to 25–30 m on the wall to see the largest gorgonians, move slowly along the face while watching the blue for sharks and pelagics, then ascend gradually along the wall to the reef top for a safety stop.

Mike Ball Dive Expeditions (Spoilsport) – 7-night Yongala & Coral Sea (Townsville–Cairns) and 10-night Coral Sea Odyssey, a few departures a year; otherwise private expedition yachts only.