Arno Bay is a small fishing and holiday town on the east coast of Eyre Peninsula, and its old jetty was built to ship grain from the surrounding farmland. It is included in this directory as one of the named Eyre Peninsula jetties, but there is little published dive information on it. The Marine Life Society notes, however, that the coast from Cowell to Arno Bay has many shallow reefs, in 2-4 m, that offer easy snorkelling, with eagle rays and Port Jackson sharks on the seagrass beds.

Under the jetty, expect the typical Spencer Gulf jetty community: algae, sponges and ascidians on the piles, with crabs, nudibranchs, small fish and the chance of seahorses or pipefish, and schools of tommy ruff, garfish and King George whiting around the structure. Squid are attracted to the lights at night, and blue swimmer crabs are common in summer. The surrounding seagrass beds are productive nursery habitat, and eagle rays and Port Jackson sharks glide over them.

The dive is shallow and easy, but visibility is often modest and fishing activity high. It suits divers travelling the Lincoln Highway who want to break the drive, snorkellers, and anyone staying in the town. For better jetty diving on this coast, Tumby Bay (leafy seadragons) lies 75 km south.

Data confidence is low; treat depths and features as indicative.

Arno Bay is on the Lincoln Highway about 45 km south of Cowell and 120 km north of Port Lincoln (roughly 560 km from Adelaide). The jetty is on the foreshore next to the hotel, caravan park and marina. Park at the jetty head and enter from the steps or beach at mid to high tide.

There is no dive shop in town; bring full cylinders or fill in Port Lincoln or Whyalla. The shallow reefs between Cowell and Arno Bay can be reached from beach access points along the coast road.

The east coast of Eyre Peninsula faces Spencer Gulf, so easterly, north-easterly and south-easterly winds blow onshore, raise chop and stir the sand and seagrass, while westerly winds blow offshore and give the flattest, clearest water. There is little ocean swell this far inside the gulf, although strong south-easterlies can produce a short, steep sea. Tides are moderate, and shallow jetties are easiest around mid to high water.

Summer afternoons often bring south-easterly sea breezes, so mornings are best; winter has more westerly weather, which suits this coast, but colder water (about 13-14°C).

Swim out along the piles to the end, search the growth and seagrass edge for small life, and return on the other side.

No operator; occasional independent divers and snorkellers.