Flagstaff is Swansea's easy, sheltered fallback dive, tucked into the bay behind Moon Island where the swell that pounds the open coast rarely gets a foothold. It's an unpretentious site: a gently sloping bottom of sand and weed beds in 5-8 m, without dramatic topography, but that simplicity is exactly the point — this is a dive for calm days, learners, or as a warm-up before or after a bigger dive elsewhere on the Swansea run. The shelter provided by Moon Island means the site can often be dived when Flagstaff's more exposed neighbours further along the coast are unworkable, making it a reliable rainy-day or blown-out-day option for local divers and visiting groups alike.The weed gardens and sandy patches support a solid variety of temperate life for a site this benign: rays cruise the sand, Port Jackson sharks tuck under ledges and weed cover (especially in the cooler months when they aggregate to lay egg cases locally), and mullet, kingfish and Australian salmon move through in season, occasionally joined by grey nurse sharks passing through on their winter migration along this stretch of coast.

Because the bottom is mostly open sand and low weed rather than structure, navigation is straightforward and the site suits open-water divers building confidence, as well as photographers looking for macro subjects in the weed beds. It is not a site to travel specifically for, but as part of a day exploring the Swansea Heads shore dives it earns its place as the calm, dependable option.

Drive from Swansea towards Swansea Heads, about five minutes from the main dive shop (Aqua Zero); park near the reserve at Swansea Heads and walk down to the small beach or rocks facing Moon Island. Choose entry point based on swell direction — the bay is well protected by Moon Island from the prevailing south-easterly swell.

Well protected from south-easterly and easterly swell by Moon Island, making this one of the more reliable shore dives on the Swansea coast when the open sites are blown out. A strong northerly swell or wind can still push chop into the bay. Visibility follows the general Swansea coast pattern — best after several calm days, worst after rain or a big swell event.

Enter from the beach or rocks, cross the shallow sand and weed gardens toward the lee of Moon Island, poking around the boulders and weed beds for rays and Port Jackson sharks, then return along the same line.

Aqua Zero Dive Centre (Swansea) runs air fills, gear hire and guided shore dives for visiting divers; Grey Nurse Charters (Newcastle) occasionally includes these sites on shore-dive days. Mostly self-guided club and personal diving.