Simpson Artificial Reef is one of two modern purpose-built fish-habitat reefs in Hervey Bay. It consists of around 15 reinforced concrete modules, each weighing up to 24 tonnes, placed in five clusters of three across about 80 ha, roughly 7 nm from Urangan Harbour in 10-16 m of water. It is named after John Simpson, the first head lighthouse keeper on Woody Island.

The reef was designed primarily for recreational fishing, and marinelife.org.au notes that purpose. Each cluster is a compact structure on sand – a set of hollow concrete shapes with openings and overhangs that attract baitfish, reef fish and predators. Growth has steadily colonised the concrete since deployment, and Hervey Bay Dive Centre includes Simpson among the sites on its local dive trips, usually when conditions suit.

As a dive, it is small-scale: one cluster per dive, circling the modules and looking into the openings for cod, sweetlips and wobbegongs, with schools of baitfish and trevally overhead. The bay's usual limits apply – visibility is often 5 m or less, tidal current runs across the site, and fishing boats are frequently anchored on the marks, so discarded line is common and divers should check the surface before ascending.

Simpson suits Open Water divers who want a different structure from the historic hulls of Roy Rufus, and is a reasonable option when the strait is running too hard for the older reef. The modules are hollow, so shine a torch into the openings – the biggest fish tend to sit deep inside – but do not put your head or body into them.

Hervey Bay's boat dives leave from Urangan Boat Harbour (Great Sandy Straits Marina / Boat Club Marina, Buccaneer Drive, Urangan), at the eastern end of Hervey Bay's Esplanade about 10 minutes' drive from Pialba; there is free parking at the marina and a public boat ramp in the harbour. Hervey Bay Dive Centre runs its local wreck and reef trips from here. Simpson Artificial Reef lies about 7 nm from Urangan Harbour – 20-30 minutes by boat.

The module clusters are marked individually (e.g. 25°11.093'S 152°57.613'E and 25°11.384'S 152°57.685'E); anchor in sand up-current of a cluster and drop back onto it.

Hervey Bay lies in the lee of K'gari, so ocean swell is rarely a problem; the limits are wind, tide and visibility. South-east trades over about 15-20 knots kick up a steep, short chop across the bay, and strong northerlies do the same in summer. Tides in the Great Sandy Strait run hard, so dives are timed for high-water slack – the Roy Rufus reef is dived only around high tide – and neap tides give the calmest water and best visibility.

Visibility is modest, typically 5 m and rarely above 10 m, and drops further after rain when the Mary River and creeks discharge into the bay (December-March). Winter (June-October) is generally calmer and clearer, and coincides with humpback whale season.

Anchor up-current of a module cluster, descend and tour the three modules, then return to the anchor line. The clusters are too far apart to swim between. Dive at slack, ideally on a neap tide.

Hervey Bay Dive Centre (Urangan Harbour) – 'Local Wreck Dives' trips to the Roy Rufus Artificial Reef and nearby sites (Goori, 3 Ships, K'gari, Iron Maria, Hardie and Simpson reefs, Snapper Grounds, Moon Ledge) on demand, timed to the high-tide slack; private boats also use the site.