Chinaman Reef is a mid-shelf reef east of Port Douglas that is better known as a navigational landmark than as a dive site. OzDive's Port Douglas site list locates Rudder Reef about 5 km west of Chinaman Ridge and South Opal Reef about 8 km east of Chinaman Reef, which places it in the band of reefs between the inshore Low Isles and the outer Opal and Agincourt reefs. Published dive descriptions of Chinaman Reef itself are scarce.

Mid-shelf reefs in this area typically offer reef slopes and patch reefs in 5–15 m, with hard coral communities that are more affected by turbidity and cyclone damage than the outer ribbon reefs but can still hold good fish life – coral trout, sweetlips, parrotfish, turtles and reef sharks. Chinaman's main value to divers is as a potential alternative when the outer reefs are blown out by strong south-easterlies, and as part of a private charter itinerary with neighbouring Rudder Reef, which OzDive describes as a sloping reef with lively bommies. The zoning also needs checking, as some mid-shelf reefs in the Cairns section are Marine National Park (Green) zones.

Chinaman Reef suits divers on private or small-group charters who want to explore a less-visited reef. It is not part of the scheduled itineraries of the large Port Douglas day boats, and anyone hoping to dive it should arrange it directly with a charter operator.

Boats leave Crystalbrook Superyacht Marina, Wharf Street, Port Douglas (car parking at the marina and on surrounding streets; courtesy pick-ups from Port Douglas and the northern beaches). Chinaman and Rudder reefs are mid-shelf reefs between Low Isles and Opal, reached in roughly 60–75 minutes. They are not on the fixed itineraries of the big day boats; small-group and private operators (ABC Reef Safaris, Scuba IQ/Blue Dive, Tech Dive Academy, OzDive) use them when wind and tide favour them or as a sheltered alternative to the outer reefs.

Entry is by giant stride from the boat at a mooring or anchorage.

Chinaman and Rudder are mid-shelf reefs, partly sheltered by the outer reefs from ocean swell but exposed to wind chop in the south-east trades (April–September). They are diveable in moderate winds when outer sites are too rough, but 20–25 knots makes the crossing uncomfortable. Visibility is usually lower than on the ribbon reefs and drops after heavy rain in the wet season (December–April) when river plumes from the Mossman and Daintree push offshore.

Stinger season November–May; cyclone season November–April. Tidal currents are moderate; neap tides give the clearest water.

Plan as a relaxed reef-edge dive from the anchorage: follow the reef slope at 8–14 m with the reef on one shoulder, turn on half gas and return along the upper slope for a safety stop on the reef top.

No fixed-itinerary day boat; used occasionally by small-group and private operators out of Port Douglas (ABC Reef Safaris, Scuba IQ / Blue Dive, Tech Dive Academy, OzDive) as a weather alternative or on private charters.