Southern Australia – South Australia, Victoria & Tasmania

Southern Australia's cool-temperate coast is a different world from the tropical reefs: kelp, sponge gardens, jetty pylons and endemic species. Leafy and weedy sea dragons live around the Fleurieu jetties (Rapid Bay, Second Valley, Edithburgh) and weedy sea dragons are reported on the Tasman Peninsula and around the Port Phillip piers. In Victoria the Port Phillip Heads Marine National Park offers tidal wall dives (Lonsdale Wall, Portsea Hole) and Pope's Eye; the ex-HMAS Canberra and ex-HMAS Hobart are scuttled naval ships made into dive sites. Many places are marine sanctuaries or no-take parks, and several are boat-only, slack-water dives for experienced divers.

Facts

• Water temperature: Port Phillip Heads about 10–22 °C (coldest mid-August, 16–20 °C peak around mid-February); SA and Tasmania not measured here, expect similar cold-temperate water
• Visibility: Pope's Eye 10–25 m, Lonsdale Wall 5–25 m (dive guide); Port Phillip Bay piers typically 6–10 m; rain cuts visibility for about two days
• Tides at the Heads: Strong tidal flow: dive times are usually a 20–30 minute slack-water window; the Heads are a designated hazardous area for boats
• Marine parks: Port Phillip Heads MNP and Ricketts Point are no-take; Encounter Marine Park (SA) has sanctuary zones around the Hobart wreck and Port Noarlunga; Upper Spencer Gulf has a sanctuary zone; Tinderbox is a Tasmanian no-take reserve
• Cuttlefish season: Giant Australian cuttlefish gather May–August near Point Lowly; in 2026 in-water access was closed for 90 days from 1 July
• Sea dragons: Leafy sea dragons resident at Rapid Bay and Second Valley jetties; weedy sea dragons at Port Phillip piers (Portsea) and Tasmania

Season

• Best months: Nov, Dec, Jan, Feb, Mar
• Acceptable: Apr, May, Jun, Jul
• Poor: Aug, Sep, Oct
• Water temperature: 10–22 °C

For the Port Phillip Heads, sources say the warmest water is November–March (with plankton-reduced visibility) and the best visibility April–July (colder); the dive guide recommends November–March for Pope's Eye and November–June for Lonsdale Wall. The giant cuttlefish season in South Australia is May–August. Season data for South Australia and Tasmania could not be sourced here.

Dive sites (27)

Port Phillip Bay & Bass Strait

• Blairgowrie Pier – beginner
• Ex-HMAS Canberra (Ex-HMAS Canberra Recreation Reserve – book mooring/tour) – 12–30 m, advanced
• HMVS Cerberus wreck, Black Rock (100 m exclusion zone – diving status unverified) – 0–3 m, beginner
• Ricketts Point Marine Sanctuary – 0–5 m, beginner

Tasmania (Tasman Peninsula & Hobart)

• Cathedral Cave, Waterfall Bay (Eaglehawk Neck) – 0–21 m, advanced
• The Sisters (off Cape Surville, Forestier Peninsula) – advanced
• Tinderbox Marine Reserve – beginner

South Australia – Yorke Peninsula & Spencer Gulf

• Edithburgh Jetty – 0–12 m, beginner
• Point Lowly / Stony Point cuttlefish aggregation (2026 in-water closure) – beginner

South Australia – Gulf St Vincent (Fleurieu, Adelaide)

• Ex-HMAS Hobart (Fleurieu Artificial Reef) – Sanctuary Zone – 5–30 m, advanced
• Port Noarlunga Reef & Jetty (Aquatic Reserve) – beginner
• Rapid Bay Jetty – 0–10 m, beginner
• Second Valley Jetty & Lassiters Reef – 0–10 m, beginner

Port Phillip Heads (Point Lonsdale & Nepean)

• Lonsdale Wall – Foggy Reef (Marine National Park) – 8–25 m, advanced
• Lonsdale Wall – North Wall (Marine National Park, part in shipping channel) – 19–60 m, advanced
• Lonsdale Wall – Paradise Wall (Marine National Park) – 10–30 m, intermediate
• Lonsdale Wall – Party Point (Marine National Park) – 12–40 m, advanced
• Merlan Inner Reef (Marine National Park) – 2–7 m, beginner
• Nepean Bay Inner East (Radar) (Marine National Park, boat only) – 1–5 m, beginner
• Nepean Reef – SS Time & Campbell wreck remains (Marine National Park) – advanced
• Outer Point Lonsdale Reef (Marine National Park) – intermediate
• Point Lonsdale Light (Marine National Park, snorkel shore dive) – 0–5 m, beginner
• Pope's Eye (Marine National Park) – 0–12 m, beginner
• Portsea Hole (Marine National Park) – 12–32 m, advanced
• SS Cheviot wreck, Point Nepean (heritage-listed – access rules unverified) – advanced
• Sweep Reef (Nepean Off-shore South, Marine National Park) – 3–9 m, intermediate
• The Springs (Marine National Park, shore dive) – beginner

Operators (3)

• Diving Adelaide – dive centre, 21-23 Grove Avenue, Marleston, Adelaide SA
• Diveline Scuba Centre – dive centre, 12 Kitson Street, Frankston, Victoria
• Eaglehawk Dive Centre – dive centre, Eaglehawk Neck, Tasman Peninsula, Tasmania

Positions are approximate unless marked 'good' (Port Phillip Heads positions are from the Parks Victoria divers' guide, ex-HMAS Hobart from the NPWS code). Many sites are marine sanctuaries/no-take parks or heritage wrecks and several are boat-only, slack-water dives; never use these positions for navigation and check current park, closure and permit rules.