South Mole is the southern breakwater of Fremantle Harbour, and the combination of the rock wall and the sand and seagrass beside it once had a reputation for weedy seadragons. Today most local divers describe it as a lot of effort for modest reward: the life is similar to other Perth groynes, the rock entry is awkward and the port is close by. It remains an option for a relaxed shallow dive or snorkel, especially from Bathers Beach.

The wall itself is made of large boulders stepping down to about 7 m. Leatherjackets, cowfish, boxfish, wrasse and red-lipped morwong use the rocks, and urchins, sea stars and small invertebrates cover them. Off the base, sand and seagrass meadows hold rays, whiting and the occasional seadragon; comb jellies drift through in some seasons. Because depths are shallow and bottom times long, divers sometimes do two dives here, one along the upper mole and one over the seagrass further in.

Bathers Beach, below the historic Round House, is the easy way in. Snorkellers use it to explore the old jetty pylons and rocky patches along the shore, and it has cafes and fish and chips close by.

South Mole suits Fremantle-based divers and snorkellers wanting a short, shallow outing. It is not worth a long drive, and the port entrance is off limits. For snorkellers and families in particular, Bathers Beach is one of the easiest and best-serviced water entries in Fremantle, and a pleasant first snorkel for visitors staying in the town centre.

From central Fremantle follow Fleet Street (past the E-Shed markets and the train station area) out along the South Mole. Several parking bays along the mole let you park, kit up and climb down the rocks; Howies used the final bays before the roundabout at the end. Parking is ticketed.

The rock scramble is the hardest part of the dive, so less experienced divers and snorkellers should enter instead at Bathers Beach, below the Round House, and swim along the inside of the mole. Do not swim into the harbour mouth.

Dive in a low south-westerly swell no greater than about 1.5 m, with a period around 11 seconds, and easterly winds. South-westerly, westerly and north-westerly winds all make the site rough and the rock entry dangerous. The summer sea breeze from the south-west typically arrives before midday, so dive early.

River outflow from the Swan affects visibility, especially after winter rain and on the ebb tide.

From Bathers Beach, swim out along the base of the inner (southern) side of the mole over sand and seagrass, holding 4–7 m, and turn well before the harbour mouth. Return along the wall or across the seagrass. From the mole itself, enter at a sheltered point on the southern side, drift along the rocks and exit at Bathers Beach if the rocks are rough.

No regular operator trips. Occasionally dived by locals and snorkelled from Bathers Beach.