Izzy's Wall is the deepest regular site on Agincourt Reef No. 2, a steep wall that falls from about 5 m to 30 m and is run either as a straightforward wall dive from the mooring or as a drift when the tide is moving. The Silverseries notes are brief – wall and drift dive with turtles, sharks, baby whaler sharks, fusiliers and anthias – but that list sums up its appeal: this is where you go for a vertical reef and the chance of young grey reef sharks. The wall is decorated with hard corals near the top giving way to sea fans, whip corals and soft corals on the steeper, deeper face.

Overhangs and cracks provide shelter for squirrelfish and soldierfish, and anthias swarm in orange-and-purple clouds wherever the current hits. Juvenile grey reef whalers – the "baby whalers" of the site description – patrol along the base, while whitetips rest on ledges. Turtles are regular, often seen feeding on sponges on the wall or rising to the surface.

Fusiliers stream past in big schools along the upper face. Because depth is available right beside you, the dive requires discipline. Most groups hold 15–20 m and work shallower, and the best colour is in the top 15 m anyway.

When the tide is running along the reef, guides turn it into a drift with a surface marker buoy and tender pick-up, which lets you cover a long stretch of wall with almost no effort. Visibility is often 20 m or better, giving a strong sense of the drop-off. The site is best suited to Advanced Open Water divers or experienced open water divers who are comfortable with depth control and drift procedures.

For divers who have done the Agincourt gardens and bommies and want something with more drama, Izzy's Wall offers a proper outer-reef wall dive and one of the better chances of seeing sharks on the day-boat circuit.

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 as a group to 18–20 m on the wall (no deeper than your certification) and drift or swim with the wall on one shoulder. Look out into the blue for sharks and turtles, gradually rise to 10–12 m by mid-dive and finish along the top of the wall at 5–6 m before a guided ascent and safety stop, with the tender collecting drifting groups.

Recreational no-decompression dive; watch NDLs on repetitive days – nitrox (EANx32) widely available on Port Douglas boats extends bottom time.

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.