Magic Mountain is the showpiece of the Outer Gneering Shoals. Visit Sunshine Coast describes 'a large group of outcrops' extending from the sandy seafloor to form 'numerous gullies, ravines, bommies, swim-throughs and pinnacles, all housing soft and hard coral colonies', and rates it a dive for more experienced divers because of its 25 m depth. SubSurface Scuba and Weekend Notes give the same description.

This is the most complex topography off Mooloolaba – a three-dimensional maze where every gully leads somewhere different. The corals and sponges are richer than on the inner reef, and the site's residents include morwong, wrasse, leatherjackets, batfish, bullseyes, butterflyfish and angelfish, with urchins, nudibranchs, anemones, feather and brittle stars, crabs and crayfish in the crevices. Wobbegongs rest in the gullies and the occasional Queensland groper cruises the reef.

The combination of depth, complex terrain and the outer reef's greater exposure to current is why it is graded for Advanced divers. Navigation is the main challenge: it is easy to lose track in the ravines, so staying with a guide and noting landmarks is important. Nitrox helps extend time at the base.

Magic Mountain is visited on calmer days when operators run to the outer reef, about 30 minutes from Mooloolaba. For experienced divers it is one of the best natural reef dives on the Sunshine Coast. The best visibility comes in winter after southerly winds, when the outcrops and swim-throughs can be seen from well above; on murky summer days the site is still rich but navigation becomes harder, so stay close to the guide and keep your route simple.

Mooloolaba's dive boats leave from The Wharf on the Mooloolah River (Parkyn Parade, Mooloolaba), about 1.5 hours' drive north of Brisbane via the Bruce Highway and Sunshine Motorway. Scuba World's shop is about 40 m from its boat, with 100+ free all-day parking spaces nearby; Sunreef departs from the same precinct. Boats run down the calm river, cross the Mooloolah River mouth beside Point Cartwright and head north-east to the reefs – about 15 minutes to the Inner Gneerings and Mudjimba Island.

Private boats can launch at the Mooloolaba (Parkyn Parade/Lions Park) ramps. Operators choose between sites on the day according to swell and current.

The Mooloolaba reefs are open-ocean sites with no shelter from the south-east trade winds or easterly swell. Operators generally cancel when winds exceed about 20 knots or swell makes the river-mouth crossing and moorings unsafe; they confirm trips by email and text around 3.30 pm the day before. Northerly winds (common on summer afternoons) also make the reefs choppy, so morning trips are more reliable.

Visibility averages about 12 m offshore (range 3-30 m) and is clearest after southerly winds and in winter; it drops after easterly blows and heavy rain. Winter (June-October) brings 19-21°C water, grey nurse sharks and humpback whales; summer (November-May) brings 25-27°C water, leopard sharks and lower visibility.

Descend to the base of the outcrops at 20-25 m, explore a ravine or gully and its swim-throughs, then work up onto the pinnacles at 15 m as your no-deco time shortens. Keep track of the route – the complex terrain is easy to get lost in. Ascend on the line or an SMB.

Nitrox recommended.

Sunreef Mooloolaba – double reef dives most days, rotating between Mudjimba Island, Nurse Rock, Hanging Rock and Caves; Scuba World Mooloolaba – reef double dives rotating through the Gneering Shoals and Mudjimba sites; SubSurface Scuba – Sunshine Coast reef double dives.