Ardrossan is the first coastal town most visitors reach on Yorke Peninsula, and its small town jetty is the easiest dive stop on the way down the east coast. The SDFSA rates it a beginner shore dive to 6 m, and local visitor information highlights the nooks and crannies under the jetty, which shelter an abundance of crustaceans. It is a modest, shallow structure over sand and seagrass, but it gives a quick taste of Gulf St Vincent jetty life without the extra hour's drive to Edithburgh.

The piles are covered in sponges, ascidians and algae, and the crevices around their bases and the debris beneath the jetty hold spider crabs and blue swimmer crabs in numbers – in late autumn and winter spider crabs can gather here as they do elsewhere in the gulf. Long-finned pike hang motionless in the shade, stingrays and fiddler rays rest on the sand, and schools of tommy ruff and garfish flicker around the end. Nudibranchs, small octopus and seahorses reward slow searching, and southern calamari are attracted to the jetty lights at night.

The dive is shallow and gentle, which makes it a practical choice for training dives, refreshers and night dives, and it is close enough to Adelaide for a day trip. The water here is generally more turbid than further south because the upper gulf is shallow and fine-bottomed, and an easterly wind can ruin visibility completely. Ardrossan also has a second, very different jetty: the long bulk-loading jetty to the north, which reaches 15 m and attracts big schools of fish but can only be reached by boat when no ship is in port (see separate entry).

Together with the nearby Zanoni wreck and Ardrossan Barge, the town is the northern base for Yorke Peninsula diving.

From Adelaide take Port Wakefield Road north and the Yorke Highway west to Ardrossan (about 150 km, 1 hour 45 minutes). Drive down to the foreshore below the cliffs; the town jetty is at the end of First Street near the boat ramp and caravan park. Park at the jetty head.

Enter via the jetty steps or ladder at mid to high tide, or walk in from the beach alongside. Do not confuse it with the long BHP/Viterra loading jetty 1.5 km to the north, which is boat-access only.

This coast faces Gulf St Vincent, so onshore easterly, north-easterly and south-easterly winds ruin it: 15 knots from the east stirs the fine sediment and drops visibility to a metre or two, and a strong south-easterly adds chop and surge. Westerly and south-westerly winds blow offshore and give the flattest, clearest water, best after a day or two of settled weather. There is no ocean swell inside the gulf.

Tides are modest (1-2 m, with 'dodge' tides of little movement), but shallow jetties are easier around high water. Autumn is calmest; summer south-east sea breezes build in the afternoon, so dive mornings. Ardrossan sits further up the gulf where the water is shallower and siltier, so visibility is generally lower than at Edithburgh and drops fast in any easterly.

Enter at high tide, drop to the sand and work along the piles to the end at 5-6 m, looking into the crevices at pile bases for crabs and pike, then return along the other side. A relaxed, shallow dive; safety stop is effectively the swim back.

No regular operator; dived independently and occasionally used by Adelaide shops and clubs as a close, easy training or night dive on the way to the lower peninsula.