Great Barrier Reef — Cairns & Ribbons

Two quite different trips leave from the same city. The Cairns day-boat fleet sails from the marina in the morning, runs an hour and a half or more out to a mooring, and fits in two or three dives before an afternoon return, sharing the deck with snorkellers and people doing their first dive. Liveaboards from the same harbour work north for three to seven nights, add night dives, and reach reefs the day fleet never sees. Choosing between those two rhythms matters more here than choosing any particular site.

On the day-boat sites the coral rises off a sandy lagoon floor in bommies and ridges cut with swim-throughs and sand gutters, shallow enough that a dive is spent looking sideways at coral rather than down into blue. The Ribbon Reefs behave differently: sheltered lagoon water on the inshore side, a face dropping toward the Coral Sea on the other, and tide pushing through the gaps between one reef and the next, which is where the drift profiles get planned and where the water actually moves.

Winter adds something the day fleet cannot promise. Dwarf minke whales gather along the northern Ribbon Reefs in June and July, in what is generally described as the only predictable aggregation of the species, and boats holding a swim-with permit trail a line for divers and snorkellers to hold while the animals decide how close to come; the codes of practice rule out chasing, baiting or following. Outside that window the set pieces are the isolated pinnacles, where a whole dive can go on circling one coral tower from the sand to its top, and the current-swept gaps where grey reef sharks hold station in the flow.

It suits divers who want warm, straightforward reef diving with very little logistical friction: boats run daily, the shore infrastructure is dense, and a non-diving partner can snorkel the same mooring. Photographers tend to do better out on the Ribbon Reefs, where the water is clearer and the subjects larger. Anyone expecting unbroken coral everywhere should temper that expectation, since successive bleaching events and cyclones have left condition patchy from reef to reef, and it is worth asking what a given operator's moorings look like in the year you go.