Pimpernel Rock is one of the more serious and less accessible dive sites on the NSW North Coast, an isolated U-shaped pinnacle rising from 40 m of water at the north-western corner of the Solitary Islands Marine Park, roughly 7.4 km off Sandon Point in Yuraygir National Park. The rock has three summits — the main one at the base of the U and two smaller ones near the tips — none rising much above 15-20 m, and the site's centrepiece is a huge natural tunnel running through the bottom of the U, a passage large enough, in the words of local operators, to fit a semi-trailer through, with its roof at about 27 m and the sand floor beneath at around 40 m. This scale of structure at this depth attracts correspondingly serious marine life: schools of well over a hundred huge jewfish and equally large aggregations of yellowtail kingfish have been reported moving through the tunnel and around the summits, trevally and giant trevally work the current lines, and grey nurse sharks are regularly found holding station in the tunnel and along the deeper walls, sheltering from the current in the same way they do at shallower sites further south.

Thousands of sea whips studded with tiger (wandering) anemones cover the rock at depth, giving the site a striking, almost coral-garden appearance despite its temperate/subtropical latitude. Access defines everything about diving Pimpernel Rock: it has no permanent mooring, sits at the very edge of what any operator on this coast will attempt, and requires calm, settled weather that can be rare through large parts of the year — trips run from Wooli, roughly 90 minutes each way, only when conditions genuinely allow, and Wooli Dive Centre requires a minimum group of about 10 divers, split into groups of three or four led by a divemaster or instructor, with a prerequisite of Advanced Open Water certification and at least 30 recent dives including deep experience. Currents here can be strong enough to sweep an inattentive diver away from the pinnacle into open blue water, and the depth of the main tunnel puts real limits on no-decompression bottom time, making nitrox a common choice for operators wanting to offer more than one dive in a day.

For experienced divers prepared to work around its access demands, Pimpernel Rock offers one of the most dramatic combinations of scale, depth and big-animal life on the entire NSW coast.

Wooli Dive Centre runs Pimpernel Rock as a special-conditions trip from the Wooli River wharf, about 90 minutes each way and only when the weather is genuinely settled; the site can also be reached from Sandon Point (closer, but only suitable for small RIBs) or from Wooli wharf (27 km, the standard route for larger vessels) or Arrawarra Headland (44 km). Diving here as a private vessel requires a Solitary Islands Marine Park permit since it lies within the Pimpernel Rock Sanctuary Zone, and a minimum group of about 10, maximum 12, split into three groups led by divemasters or instructors is the standard charter format.

North Solitary Island and Pimpernel Rock sit fully in the open ocean north of the more sheltered Coffs Harbour grounds, so trips depend on a genuinely settled weather window — under about 1.5 m swell and light-to-moderate winds — and are cancelled more often than the South Solitary Island trips run from Coffs. The Wooli River bar itself is shallow and can be dangerous in a big swell or a strong outgoing tide; the dive centre's shallow-draft, high-powered vessel is built specifically to manage it, but the bar can still close the operation down on a bad day. Visibility offshore is normally excellent, in the order of 15-30 m, but summer brings warmer water (up to 25°C) with more current from the East Australian Current, while winter is cooler (down to about 18-19°C) but often calmer.

Cyclone-influenced swells from the Coral Sea can affect this coast in late summer/early autumn even without a direct cyclone hit. Pimpernel Rock is the most exposed and remote site covered by any operator on this stretch of coast, so it needs a longer and more reliable settled-weather window than any of the inshore or South Solitary Island sites; visibility can also drop noticeably after heavy rain despite the distance offshore.

Descend directly onto one of the three summits (as shallow as 10-15 m) or straight to the tunnel entrance at around 27 m depending on the plan, pass through the huge tunnel watching for grey nurse sharks in the deeper cave areas and large jewfish and kingfish schools, and ascend along the pinnacle wall rather than into open water given the current; bottom time is limited by the depth and nitrox is recommended for multiple dives in a day.

Not a decompression dive if kept to the summits/tunnel roof (27 m), but bottom time is tight; nitrox recommended for repeat dives; treat the tunnel as an overhead swim-through requiring good buoyancy and a torch.

Wooli Dive Centre is the primary operator, running Pimpernel Rock only in calm weather with a minimum group of about 10 divers split into groups of 3-4 led by a divemaster or instructor; minimum experience required is Advanced Open Water with at least 30 recent dives including deep diving. Jetty Dive Centre (Coffs Harbour) occasionally includes it on extended trips.