Second Reef is a long ridge of branching coral that forms the enclosing shoulder of the great sandy patch on Lady Elliot's western side, gradually deepening towards the Lighthouse. At 5-12 m it is one of the island's shallower sites, recommended by the resort for divers who prefer shallow dives. The branching corals and anemones host coral trout, yellowfin goatfish, chromis and fusiliers, and green, loggerhead and hawksbill turtles are common.

Blue-spotted lagoon rays rest on the sand at the edge of the ridge, and giant trevally sweep through. Marine life writers add whitetip and grey reef sharks, sweetlips, snapper, Maori wrasse, mackerel, angelfish, lionfish, barramundi cod, groper, octopus and crayfish to the list. The ridge makes navigation simple, and the shallow depth gives long bottom times in bright light.

It suits new divers and photographers, and it is sheltered in the prevailing winds. The Oceanity guide lists several nearby named moorings along the same reef system, including Sandy Seconds, Reefy Seconds, Nemo Wall and Turtle Beds, which are variations on the same shallow western reef. Second Reef was grouped with Shark Pool in the earlier database pass; Shark Pool is a separate northern site and now has its own row.

The ridge is also a useful snorkel from the boat in calm conditions, and it is one of the best places at Lady Elliot for new divers to log a long, relaxed dive among turtles. Turtle numbers peak during the summer nesting season, when adults gather off the island before coming ashore; the top of the ridge comes within a few metres of the surface, so turtles are often visible from above.

Lady Elliot Island is the southernmost coral cay of the Great Barrier Reef, about 80 km north-east of Bundaberg, and is reached only by the resort's light aircraft from Bundaberg, Hervey Bay, Brisbane (Redcliffe) or the Gold Coast (baggage limit about 15-16 kg, extra dive-gear weight bookable). From the airstrip, walk to the resort dive shop; boats are launched from the western beach or the lighthouse side and all dive sites are 10 minutes or less by boat. Second Reef is on the western side, a few minutes by boat.

The island has a western (lee) side and an eastern (windward) side. Under the prevailing south-east trades the western sites (Lighthouse Bommies, Coral Gardens, the Severance) are sheltered and dived most days; the eastern wall sites (Blowhole, Tubes, Hiro's Cave) need light winds or a westerly/northerly. Swell over about 2 m from the south-east closes the eastern side, and strong northerlies (spring/summer) make the west choppy.

Tidal range is about 2-3 m; currents are strongest at the southern tip. Summer brings warmer water but more plankton and occasional cyclones (November-April). Western sites are the default in the prevailing south-easterlies; they become choppy in strong northerlies or westerlies.

Descend onto the ridge at 6-8 m and follow it along, alternating between the branching coral on top and the sandy edge for rays, gradually deepening towards the Lighthouse end. Turn at half air and return shallower.

Lady Elliot Island Eco Resort's PADI dive shop is the only operator: guided boat dives twice daily (early morning and afternoon, bookings open the day before), plus courses; boat rides are 10 minutes or less and all sites are moored. Day-trip packages from Bundaberg, Hervey Bay and the Gold Coast include diving. The resort does not offer shore dives.