Tankerton Jetty is the gateway to French Island, the large, sparsely populated island that fills the middle of Western Port, and The Scuba Doctor lists it as a 3–8 m pier dive on the island's western shore – almost certainly the least-dived pier in Victoria, since reaching it means carrying full scuba gear onto the passenger ferry from Stony Point. It is an operational jetty serving the ferry and various commercial vessels, and the source's advice is entirely about that: stay vigilant around boat traffic, keep clear of working areas, and use a dive flag. Underwater the jetty offers the Western Port channel habitat seen at Stony Point – pylons with hydroids, mussels and sponge growth scoured by the tide, a bottom of sand, shell and seagrass shelving to 8 m, and fish that move with the current: whiting, salmon, trevally, mullet, flathead, squid and rays, with the seagrass beds off the island supporting more life than the mainland shore because French Island is largely national park and its waters are little disturbed.

The tidal streams are strong, so it is a slack-water dive of half an hour or so, and visibility is a few metres at best. The appeal is the adventure rather than the reef: a ferry ride across the channel, an island with more koalas than people, and a pier nobody dives, followed by the wait for the boat home. It suits experienced, self-sufficient divers and clubs looking for something different, and it is best treated as a day trip combined with the island's walking tracks.

Anyone wanting a rewarding Western Port dive with less logistics should go to Flinders Pier.

French Island has no vehicle ferry for visitors, so divers take the passenger ferry from Stony Point Pier (about 10–15 minutes) carrying their own gear – cylinders and weights included – and walk off the jetty at Tankerton. Enter from the beach beside the jetty or a ladder on the structure, keeping clear of the ferry berth and freight operations. Exit the same way and catch a later ferry back; check the timetable, which is infrequent outside peak times.

Alternatively cross by private boat and anchor off the jetty.

Tankerton lies on the eastern side of Western Port's western channel and has the same strong tidal streams as Stony Point opposite; dive only at slack water, ideally high-water slack, and expect the ebb to build quickly. The jetty faces west and is exposed to westerly and south-westerly chop, sheltered from easterlies by the island. Visibility is estuarine and drops after rain.

Ferry and freight movements dictate when the jetty can be approached – divers must stay well clear of working areas and fly a flag at all times.

Enter from the beach beside the jetty just before high-water slack, follow the pylons out to 5–8 m on the side away from the ferry berth, and return along the same pylons as soon as the current is felt; surface close to the beach, never in the berth.

No regular operator; a rare club or private-boat dive. The French Island ferry from Stony Point is the only public access.