Kingscote Jetty is the easy, dependable dive of Kangaroo Island and the usual first dive for anyone coming to the island. Three jetties sit side by side off the Kingscote foreshore, sharing a car park, and the main jetty has both a ladder and a ramp. The bottom slopes gradually over sand and seagrass from about 1 m to 6-8 m at the outer end, depending on the tide.

Its reputation rests on critters. Diving Adelaide's trip report lists nudibranchs, blue-ringed octopus, leafy sea dragons and seahorses, and other accounts add weedy seadragons, giant cuttlefish (present year-round, peaking in the winter breeding season), rays, crabs and schools of juvenile fish. The pylons are encrusted with sponges and ascidians, and the seagrass fringes are where seadragons are most often found. It is a macro and photography dive: move slowly, look closely, and the jetty will fill an hour easily. Water is noticeably colder than on the mainland – Diving Adelaide noted it was about 4°C cooler than Rapid Bay in summer.

The jetty functions as an acclimatisation dive before the island's more exposed reefs and wrecks, and as a fall-back when the north and south coasts are rough, since Nepean Bay is sheltered from the prevailing south-westerlies. Night dives bring out octopus, squid and crustaceans. With the town's cafes, accommodation and the local dive shop within walking distance, it is about as convenient as island diving gets. It suits beginners, photographers and anyone waiting for the weather to open up the rest of Kangaroo Island.

Take the SeaLink ferry from Cape Jervis to Penneshaw (45 min), then drive about 60 km (45-50 min) west to Kingscote. The jetty is on the town foreshore off Kingscote Terrace, with a car park at the base shared by three jetties. Gear up at the car; the main jetty has a ladder and a ramp that reaches the water at about a 0.5 m tide.

Kangaroo Island Dive & Adventures is on Kingscote Terrace a short walk away (confirm fills in advance).

Nepean Bay faces north-east and is sheltered from the prevailing south-westerly swell, so Kingscote's sites are diveable on most days of the year. Strong north-easterly to easterly winds push chop into the bay and cloud the water; south-westerly gales have little effect beyond wind chop. Tidal movement is modest, but visibility is best on a high tide and after several calm days.

Summer afternoon sea breezes add surface chop – mornings are best. Autumn and winter often bring the clearest water.

Enter from the ladder or ramp, descend to the sand and weed at 3-4 m and swim out under the jetty, checking pylons for nudibranchs and seahorses and the seagrass edges for leafy and weedy seadragons, to the end at 6-8 m. Return via the other side or the neighbouring jetty; safety stop on the pylons.

Kangaroo Island Dive & Adventures (15 Kingscote Terrace, Kingscote – PADI centre, fills, hire, guided shore and boat dives; confirm current trading) – guided shore dives; Diving Adelaide runs Kangaroo Island leafy seadragon trips that include Kingscote Jetty.