Nursery Bommie is the Agincourt site the Port Douglas crews save for their best days. Silverseries and Poseidon both describe it as a stunning 24 m pinnacle considered one of the best sites in the area, and the Visit Port Douglas Daintree dive guide picks it out as a highlight of the Agincourt complex. The bommie rises from a sandy bottom at around 24 m almost to the surface, a single column of reef covered in gorgonian sea fans, soft corals and hard corals.

Its isolation means it acts as a magnet for fish: whitetip and grey reef sharks cruise around the base, stingrays rest on the sand, and barracuda and trevally hang off the sides in the current. Drummers and snapper school around the upper slopes, anthias swarm over every outcrop, and moray eels peer from holes in the pinnacle's sides. The name comes from the abundance of juvenile tropical fish sheltering in the coral, and garden eels sway from the surrounding sand.

Divernet's account describes a shallow sandy area nicknamed the Fishbowl, ringed by branching staghorn coral, which makes a perfect place to end the dive and do the safety stop among small reef fish. The classic dive plan is a spiral: start deep on the up-current side while you have the most gas, work your way around the pinnacle, then climb slowly so the colourful upper walls fill the second half of the dive. Current can run past the bommie, so it is best suited to divers comfortable at 20 m+ and able to hold position in some water movement; operators may restrict newer divers to the upper part.

Visibility is commonly 20 m or better, which lets you see much of the pinnacle at once – a big part of its appeal. It is a superb photographic site for wide-angle work, with fans and schooling fish silhouetted against the blue. If you only get one dive at Agincourt, this is the one to ask for.

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.

Descend to the base of the pinnacle (22–24 m) on the up-current side, circle slowly for the first 10–12 minutes looking for sharks, rays and the barracuda over the sand, then spiral up. Spend the second half of the dive at 8–12 m exploring the gorgonians and soft corals, and finish on the top of the bommie or in the shallow 'fishbowl' garden for the safety stop.

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.