Walmart is a Bougainville Reef wall site. Marinelife.org.au gives a depth of 20 m and describes a wall with a 700 m drop-off, known for colourful invertebrate diversity, with butterflyfish, humbugs, fairy basslets and nudibranchs. The name, like the neighbouring Corner Shop, plays on the idea of a reef well stocked with things to see.

Corner Shop, Silver Slope and Southern Wall now have their own rows.

The wall starts a few metres below the reef edge and falls sheer into the depths. Its face is covered in soft corals, sponges, sea fans and encrusting invertebrates, which makes it a site for slow, close-focus diving rather than big-animal spotting. Fairy basslets swarm along the face, humbugs dart in and out of branching coral, butterflyfish pick at the reef, and nudibranchs crawl among the sponges. Grey reef and whitetip sharks patrol the drop-off, as at all Bougainville sites.

The visibility, typically 20–40 m, makes even a macro-focused dive feel expansive. Walmart suits intermediate divers comfortable on a wall and is a good choice for photographers with a macro lens. It is not listed on current Mike Ball itinerary pages, so it is probably dived only occasionally when the crew wants a sheltered wall with plenty of small life. Bring a torch to bring out the colours on the face.

Liveaboard only. Mike Ball's Spoilsport visits Bougainville on its 4-night Osprey fly-dive (Cairns departure Thursday evening, return by flight from Lizard Island), 5-night Coral Sea & Cod Hole and 7-night Coral Sea expeditions; the overnight run from Cairns is roughly 230 km of open ocean. Bougainville is not guaranteed on every itinerary and is usually allocated one day.

Walmart is dived from a mooring or tender drop at the crew's discretion.

Bougainville is a small, isolated Coral Sea reef about 230 km north-east of Cairns and 150 km south of Osprey, with no land to shelter behind, so the surface can be choppy in any SE trade wind over about 20 knots, common June to August. Conditions broadly follow Osprey's, though Bougainville is sometimes calmer when Osprey is windy. Currents are generally mild but can pick up on the corners and walls.

September to December usually gives the calmest seas and best visibility (20–40 m); December to April is cyclone season.

Descend to about 20 m on the wall and follow it slowly, concentrating on the invertebrate life and small fish on the face. Rise gradually along the wall and finish on the reef top.

Coral Sea liveaboards visiting Bougainville (Mike Ball Dive Expeditions) – occasional.