Portsea Hole

Wall DiveWall Dive | Boat access

Inside Port Phillip Marine Park - No Fishing Open Water Rated Reef Dive Site Slack Water

Depth: 12 metres (39 feet) to 33 metres (108 feet)

Portsea Hole Bathymetry
Portsea Hole Bathymetry
© Parks Victoria

Portsea Hole is inside Port Phillip about 500 metres (1,640 feet) from the Portsea Pier and is a remnant secion of the drowned valley of the Yarra River. The surrounding seabed marks the top of Portsea Hole at 12 metres (39 feet) and to the North there is a vertical wall approximately 75 metres (246 feet) long which drops to sand at 27 metres (89 feet), then into a sand bowl which bottoms at 33 metres (108 feet).

Portsea Hole | Credit: OzMarineBoy

Portsea Hole is a remnant section of the Yarra River with calcarenite vertical reef. Its moderately exposed, vertical and sloping reef is orientated east in a natural amphitheatre. It consists of rocky ledges and outcrops on the western side of a sandy bowl or hole. At the top of the hole there is a largely flat area with very low steps (0.5 m) and a few rock bombies. This area is covered by patches of sand and algae. In the hole there is a narrow strip of vertical reef wall and ledges at 22 metres (72 feet) depth, approximately 2 metres (6.6 feet) high and 20 metres (66 feet) long, which supports mostly sessile invertebrates. There is also a small area of rocky outcrop at 27 metres (89 feet) depth interspersed with sand. On the wall algae grows on horizontal reef surfaces, and is limited by low light from the overhanging ledges.

Portsea Hole Scan

Portsea Hole is characterised by diverse and abundant fish assemblages as well as a rich benthic community of marine invertebrates, encrusting algae, sponges and soft corals. The wall comprises small overhangs, which are home to a vast array of invertebrate life and fish, in particular the beautiful Blue Devil fish. On the top of the hole there are several rock Bommies that host hundreds of fish of many species.

Vertical sections of Portsea Hole support a high abundance and diversity of sessile invertebrates, including sixteen different types of sponges such as arborescent, flabellate, encrusting and massive sponges. Massive ruffled sponges can be particularly abundant on the reef. The relative dominance of sponges can change over time.

Portsea Hole has a high abundance and diversity of fish species including barber perch, southern hulafish and silver sweep. Other commonly seen fish species include the blue devil fish, butterfly perch, jackass morwong, gurnards and goat fish.

Portsea Hole has moderate exposure to waves and currents. It is best dived at slack water. You might also like to take a look at the nearby Portsea Hole Wreck

See also Wikipedia: Portsea Hole, and
Parks Victoria: Portsea Hole.

Portsea Hole Dive Boats
Portsea Hole Dive Boats
© Dolphin Research Institute

Portsea Hole is is a very popular boat dive site for recreational scuba diving activities. More than one Melbourne diver has had their first taste of scuba diving from a boat here.

This site lies in the Port Phillip Heads Marine National Park. The park is made up of six separate marine areas around the southern end of Port Phillip: Swan Bay, Mud Islands, Point Lonsdale, Point Nepean, Popes Eye, and Portsea Hole.

See also, Parks Victoria: Port Phillip Heads Marine National Park,
Port Phillip Heads Marine National Park - Map (PDF 1.4 MB),
Divers Guide - Port Phillip Heads Marine National Park (Adobe PDF | 7.72 MB), and
Port Phillip Heads Marine National Park Identification Booklet (Adobe PDF | 16.34 MB).

Latitude: 38° 18.684′ S   (38.3114° S / 38° 18′ 41.04″ S)
Longitude: 144° 42.651′ E   (144.71085° E / 144° 42′ 39.06″ E)

Datum: WGS84 | Google Map
Added: 2012-07-22 01:00:00 GMT, Last updated: 2020-05-17 08:03:58 GMT
Source: GPS
Nearest Neighbour: Portsea Hole Wreck, 36 m, bearing 336°, NNW
Depth: 12 to 33 m.
Dive only on: SWF, SWE.
Mean water temp - summer: 18.4°C.
Mean water temp - winter: 12.5°C.

DISCLAIMER: No claim is made by The Scuba Doctor as to the accuracy of the dive site coordinates listed here. Should anyone decide to use these GPS marks to locate and dive on a site, they do so entirely at their own risk. Always verify against other sources.

The marks come from numerous sources including commercial operators, independent dive clubs, reference works, and active divers. Some are known to be accurate, while others may not be. Some GPS marks may even have come from maps using the AGD66 datum, and thus may need be converted to the WGS84 datum. To distinguish between the possible accuracy of the dive site marks, we've tried to give each mark a source of GPS, Google Earth, or unknown.

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