North Boulder Wall sits on the lee, north-western side of South Solitary Island, and because it faces away from the prevailing easterly and south-easterly swell that affects the more exposed Manta Arch and Shark Gutters, it is one of the most consistently diveable sites in the group and a favourite second or third dive on a day when the outer moorings have already been visited. The wall is not a sheer drop-off in the classic sense but a broad, boulder-strewn platform at 8-12 m that spills over its edge in a cascade of large rocks down to a comfortable maximum of about 18 m. The boulders themselves are richly colonised and support an unusually high density of resident reef fish for a site this shallow: crayfish shelter in the crevices, blue tang, silver trevally, goatfish, tarwhine, red morwong and snapper move through in numbers, and giant cuttlefish are a highlight through the cooler months when they move onto the shallower reef to breed.

Turtles use the wall as a resting and feeding ground, grazing on the algae covering the rock, and the general fish density here rivals the more current-affected sites without the same exposure risk. Because of its gentle depth range and sheltered aspect, North Boulder Wall is regularly used for less experienced divers and as a relaxed, colourful dive to pair with a more demanding morning dive at Manta Arch or Shark Gutters. It also links directly with South Boulder Wall a short distance along the same face of the island, giving operators the option of a longer drift along the full length of the wall on days with a little current.

For visitors wanting an easy, reliably good dive at South Solitary Island regardless of conditions elsewhere in the park, this is usually the site Jetty Dive Centre falls back on.

Jetty Dive Centre departs from a public floating pontoon wharf on the Coffs Harbour boat harbour, opposite the Attitude Burgers building — check in first at 398 Harbour Drive, Coffs Harbour. It is roughly a 30-40 minute run out to South Solitary Island, 8 km offshore, in the dive centre's RIBs. Private boats launch at the Coffs Harbour public boat ramp inside the breakwall and follow the same course out past the harbour entrance.

South Solitary Island sits in open water 8 km off Coffs Harbour and is exposed to swell from the north-east through south-east; Jetty Dive Centre generally wants under about 1.5-2 m swell to run the outer moorings comfortably, switching to the more sheltered Split Solitary Island (only 20 minutes out) on rougher days. Visibility here is usually the best in the marine park given the distance from any river mouth, and the site's position at the boundary of tropical and temperate water means conditions can change quickly with wind shift. Summer (Nov-Apr) water is warmed by the East Australian Current to up to 26°C, bringing tropical fish, manta rays and, from December, leopard sharks; winter (May-Oct) cools to about 18°C but often gives calmer seas, giant cuttlefish and the peak grey nurse shark season (Jun-Nov, sometimes 30-60+ sharks on Manta Arch).

Humpback whales migrate past between April and November, peaking June-August northbound and September-November southbound. Currents can run strongly on the exposed north-eastern moorings (Manta Arch, Shark Gutters) and are much gentler on the sheltered north-western wall.

Descend the mooring to the 8-10 m platform, work along the boulder-covered wall down to about 18 m looking for crayfish and giant cuttlefish, and finish shallow along the platform top for an easy ascent.

Jetty Dive Centre (Coffs Harbour) runs South Solitary Island most days conditions allow, typically a double boat dive; it is the flagship site for the only major dive operator based in Coffs Harbour.