The Gardens is the shallow end of the Agincourt spectrum: a lagoon-type site on Agincourt Reef No. 2 where a mass of large boulder corals sits on a sandy floor no deeper than about 10 m. With visibility averaging around 20 m and often reaching 30 m, the whole site is flooded with light, and it is frequently run as a gentle drift so divers can cover a wide area of reef with minimal effort. The appeal is the density of coral heads and the fish that live among them.

Massive Porites and other boulder corals, some several metres across, form a maze of rounded mounds separated by sand channels. Feather stars perch on the tops, Christmas tree worms dot the coral surfaces, and every head has its own little community of chromis, damsels and cardinalfish. Parrotfish graze audibly on the coral, goatfish sift through the sand in loose groups, and fusiliers stream overhead.

Milkfish sometimes cruise through in silvery schools, and titan triggerfish nest in the sand – they are worth giving a wide berth in the nesting season. Because it is so shallow, The Gardens is ideal for new divers, discover-scuba participants and snorkellers, and it is a sensible choice for a second or third dive when you want to reduce nitrogen loading. Photographers get reliable ambient-light colour without strobes.

When the tide is running the guide will drift the group along the reef, with the boat's tender collecting divers at the end; on slack water it becomes a simple out-and-back from the mooring. Either way the dive is relaxed and navigation is easy – the main thing to manage is buoyancy close to the coral heads. The site sits within the Agincourt complex's protected zoning and is part of the daily rotation for the Port Douglas day boats.

It will not give you the dramatic walls of the outer face, but for colour, fish density and easy conditions it is one of the most enjoyable shallow dives in the area.

Agincourt day boats leave Crystalbrook Superyacht Marina (formerly the Reef Marina) on Wharf Street, Port Douglas, between about 8:00 and 8:30 am. Park in the marina car park or the free all-day street parking around Wharf and Dixie streets; Quicksilver, Poseidon and Calypso also run coach pick-ups from Port Douglas, Palm Cove and northern Cairns beaches. The run to the Agincourt ribbon reefs on the edge of the continental shelf is about 65–70 km north-east and takes roughly 75–90 minutes on the large catamarans (Silversonic is the fastest), longer on small-group boats such as Scuba IQ/Blue Dive.

You gear up on board and giant-stride from the dive deck at a permanent mooring; the skipper picks the sites on the day to suit wind and tide, so a named site is never guaranteed. Boats are back at the marina around 4:30 pm.

Agincourt is an outer ribbon reef on the shelf edge, so it is fully exposed to the south-east trade winds that blow from about April to September. Moorings on the protected western (back-reef) side remain diveable in 15–20 knots, but anything over 25 knots or a 2.5 m+ sea makes the crossing rough and operators may cancel or switch to more sheltered moorings. Calm spells in October–December give the glassiest days and 30 m+ visibility.

The wet season (December–April) brings northerlies, afternoon storms, cyclone risk and occasional reduced visibility after big rain events, although the outer reef is far less affected by run-off than inshore reefs. Marine stingers are present November–May. Tidal currents run along the reef edges and through the gaps between the Agincourt reefs; spring tides strengthen them, so exposed corners are usually dived on the neaps or near slack water.

Usually run as a slow drift: drop in with the guide, settle at 6–8 m and let the tide carry you over the boulder coral field, weaving between heads rather than swimming hard. Stay together with your buddy, keep one eye on the guide's surface marker buoy and ascend together at the end of the drift for a pick-up by the tender, doing the safety stop mid-water or on a coral head at 5 m.

Quicksilver Silversonic – daily, 3 dives across Agincourt 1–4; Poseidon (Quicksilver Group) – daily, 3 sites at Agincourt; Calypso Reef Cruises – regular Agincourt days; Scuba IQ / Blue Dive and Tech Dive Academy – small-group day trips several days a week.