Flinders Pier is the best place in the world to see weedy seadragons, and the claim is made by people who have looked elsewhere. The pier, first built in 1864 and listed on the Victorian Heritage Register, runs about 330 m out into the western entrance of Western Port beneath West Head, and beneath it lies a bottom quite unlike the sand of the Port Phillip piers: fine sand at the root giving way to dense seagrass meadows of Zostera and Amphibolis, colonised by sponges and hydroids, over which dozens of resident weedy seadragons drift at 3–4.5 m. They are present year-round, most numerous from August to March, and from September the males carry clutches of eggs on their tails.

The seadragons made the pier famous – it featured in the BBC's Blue Planet II – but they are only part of the cast. Shaw's cowfish are unusually numerous, giant Maori octopus hunt the pylons, big smooth stingrays (protected within 400 m of Victorian piers) and eagle and fiddler rays cruise the sand, draughtboard sharks and Melbourne skates rest under the seagrass, and old wives, silver trevally, bluethroat wrasse and goatfish school around the growth. At the pier head an old engine block and wreck debris form a small reef, and at night the pylon anemones glow pink, orange and red.

Australian fur seals and dolphins visit, and leafy seadragons have been photographed here on rare occasions. Flinders is also a story about a pier: the inner timber section deteriorated and was closed for years, Parks Victoria proposed demolishing it, and a community campaign secured heritage listing and an $18 million restoration that began in late 2025 – only to be halted in April 2026 when funding ran out, so access arrangements remain in flux. Divers should also know that visibility here is famously fickle and that the site is exposed to Bass Strait swell.

It suits everyone from Open Water students to specialist photographers, and no Victorian dive log is complete without it.

Flinders is 100 km from Melbourne via the Mornington Peninsula Freeway and Boneo or Frankston–Flinders Road; the pier is at the bottom of The Esplanade below the village. Park in the large free car park south of the pier beside the boat ramp, 80 m from the water, and gear up there; a trolley is useful for the walk along the pier. The easiest entry is the lower landing with its steps and ladders (submerged at high tide, when you simply step in); several ladders and step platforms along the pier serve as exits, or walk in from the beach on the northern side.

The old inner timber section has been closed to pedestrians for years and is under restoration – check Parks Victoria for current access, since the closure may force a beach entry and a longer swim.

Flinders Pier is on the ocean side of Western Port and behaves differently from the Port Phillip piers: it is best with light-to-moderate offshore north-westerly to south-westerly winds and is blown out by strong north-easterly to south-easterly winds, which push Western Port chop straight onto it. Any significant Bass Strait swell wrapping around West Head produces surge under the pier and destroys visibility. Dive at slack water or on the incoming tide – the tidal range is about 1.5 m and the ebb carries silt out of the bay – and prefer high tide for depth.

Visibility is notoriously unpredictable, from 10 m to arm's length on consecutive days, and is worst after rain. Late morning often improves as the sun gets on the seagrass.

Enter at the lower landing, descend to 3 m and work slowly along the pylons toward the pier head, scanning the seagrass and Amphibolis beds on either side for seadragons at 3–4.5 m; at the head, check the old engine block and wreck debris. Return along the other side of the pier, spending time on the pylon growth for nudibranchs and cowfish, and exit at a ladder or the landing.

Bayplay (Portsea), The Scuba Doctor (Rye, 30 minutes away), Dive Victoria, Extreme Watersport and Melbourne dive shops run guided seadragon dives and Open Water training here throughout the year; photographers and independent divers dive it daily. No charter needed.