The Grotto, Labyrinth and Interlinked Caves form a connected cave and grotto system at Seal Rocks that local operators rate among the best sea cave dives anywhere on the NSW coast, and the description is not hyperbole given the combination of genuine passage complexity and one of the area's most photogenic natural effects: sunlight streaming through grotto openings backlights grey nurse sharks holding motionless in the chambers, creating a striking silhouette that has become something of a signature image for Seal Rocks diving. The system runs from a shallower Grotto entrance around 12 metres down through a genuinely maze-like Labyrinth section to the deeper Interlinked Caves around 33 metres, giving experienced cave-trained divers a substantial, multi-chambered environment to explore rather than a single short passage. Beyond the sharks and the light effects, the caves support typical Seal Rocks invertebrate and fish life in their more sheltered recesses, and the complexity of the passage network means this is genuinely a site for divers with cave or cavern training, or at minimum an experienced local guide who knows the layout thoroughly, rather than an open-water diver's casual exploration.

Because of the depth range, the overhead environment and the several named sections that together make up the system, this is typically treated as a signature, must-do dive for visiting technical or cave-experienced divers coming to Seal Rocks specifically, and Forster Dive Centre includes it as a highlight of the Seal Rocks itinerary when conditions and diver qualifications allow. The combination of maze-like topography, resident sharks and dramatic natural lighting makes it one of the most distinctive dives anywhere on the mid-north coast.

Boats for the Seal Rocks sites either run the longer distance down from Forster/Tuncurry (about 45-60 minutes) or launch locally from the small boat ramp at Seal Rocks village itself, near Sugarloaf Point, cutting the run to Big and Little Seal Rock down to 10-20 minutes. Seal Rocks is a small, remote settlement reached via Lakes Way/Mungo Brush Road through Myall Lakes National Park; there is no dedicated dive shop in the village itself, so most Seal Rocks charter diving is booked through Forster Dive Centre, with divers sometimes meeting the boat locally rather than travelling from Forster.

Seal Rocks sits on an exposed headland with Sugarloaf Point taking the full force of easterly and south-easterly swell — trips are cancelled in anything beyond about 1.5 m swell, and the site is often diveable when more sheltered locations further north are blown out, or vice versa, so conditions should always be checked specifically for Seal Rocks rather than assumed from Forster. Visibility is typically 15-30 m and can be excellent in settled autumn and winter weather; it drops after the Myall Lakes and Wallis Lake systems discharge following heavy rain. Grey nurse sharks are present at almost any time of year here, with numbers varying seasonally, and the wrecks (Satara, Catterthun) require calm, low-current conditions for safe deep/technical diving.

Descend to the Grotto entrance (12-23 m) and work through the interlinked passages toward the deeper Labyrinth and Interlinked Caves sections (to 33 m), pausing where grotto openings let light stream in and backlight any grey nurse sharks holding in the chambers, before retracing the route to exit.

Recommended for cave/cavern-certified divers or under close experienced-guide supervision; plan gas conservatively given the multi-chamber layout and depth.

Forster Dive Centre (Tuncurry) — regular boat trips to Seal Rocks, year-round, weather permitting.