Reefwander
Blue-spotted maskray resting on a sandy bottom scattered with rubble and weed — South West Rocks

Australia & New Zealand · Australia

South West Rocks — Fish Rock

A 125 m ocean through-cave, and grey nurse sharks in the gutters

Photo: Richard Ling · CC BY-SA 2.0

Fish Rock sits two kilometres off the New South Wales coast, and a 125 m tunnel runs right through it — one of very few true ocean through-caves anywhere. Divers enter the deep end at 24 m, swim in darkness past resting wobbegongs and cave shrimp, and exit into a gutter at 12 m. The rock is also a critical aggregation site for grey nurse sharks, a critically endangered population on this coast, which hang motionless in the gutters in numbers through winter and spring.

About diving in South West Rocks — Fish Rock

Everything here runs off a boat. Operators launch from South West Rocks, the run out takes only a few minutes, and the standard trip is a double dive with the surface interval spent afloat, so a morning charter has you back on the ramp by early afternoon. Fish Rock is exposed on every side to the open Pacific, so swell cancels charters at short notice, often at dawn on the day itself. Anyone travelling specifically for the tunnel should budget three or four diving days rather than pin the trip on one.

Outside the tunnel the rock is a separate dive. The sides drop into boulder fields and sand gutters, ledges and overhangs run around the base, and the seaward face takes whatever current is running. Wobbegongs rest under the ledges, crayfish back into the cracks, and schooling fish hold off the corners where the water moves. Divers staying several days tend to alternate, one dive inside in the dark and the next outside in the light, and the cave is optional, so a buddy who would rather skip the overhead still gets a dive.

The through-swim is treated seriously. It is dived one way, from the deep entrance towards the shallow exit, in single file, with silt on the floor that a careless fin will lift and a middle stretch where neither end is visible. Carry your own torch rather than sharing one, and sort out kit before you enter. The sharks are the other reason people come: they hold station in the gutters facing the flow, and because the rock is protected habitat the briefing covers how to approach, slowly and low, and when to back off.

It suits divers already settled in an overhead environment and content with cool green-blue temperate water rather than reef colour. The seasonal trade-off is real: shark numbers build through the cooler half of the year, when a 7 mm suit and hood are the norm, while the warmest and clearest water arrives early in the calendar year with fewer animals holding in the gutters. Divers after shallow reef variety will find the destination narrow, since it is one rock dived repeatedly plus a short list of inshore fallbacks.

Best time to dive South West Rocks — Fish Rock

South West Rocks — Fish Rock season rating, sea surface temperature, daytime high and rainfall by month, 2011–2025 averages
JanFebMarAprMayJunJulAugSepOctNovDec
SeasonGoodGoodGoodGoodGoodPrimePrimePrimePrimePrimeGoodGood
Sea surface25°C77°F26°C79°F26°C79°F25°C77°F23°C73°F22°C72°F20°C68°F20°C68°F20°C68°F21°C70°F22°C72°F23°C73°F
Daytime high30°C86°F29°C84°F28°C82°F26°C79°F24°C75°F22°C72°F21°C70°F23°C73°F25°C77°F27°C81°F29°C84°F30°C86°F
Rain197 mm7.8 in213 mm8.4 in233 mm9.2 in89 mm3.5 in67 mm2.6 in87 mm3.4 in39 mm1.5 in48 mm1.9 in37 mm1.5 in90 mm3.5 in121 mm4.8 in146 mm5.7 in
South West Rocks — Fish Rock season rating, sea surface temperature, daytime high and rainfall by month, January to June, 2011–2025 averages
JanFebMarAprMayJun
GoodGoodGoodGoodGoodPrime
Sea surface
25°C77°F26°C79°F26°C79°F25°C77°F23°C73°F22°C72°F
Daytime high
30°C86°F29°C84°F28°C82°F26°C79°F24°C75°F22°C72°F
Rain
197 mm7.8 in213 mm8.4 in233 mm9.2 in89 mm3.5 in67 mm2.6 in87 mm3.4 in
South West Rocks — Fish Rock season rating, sea surface temperature, daytime high and rainfall by month, July to December, 2011–2025 averages
JulAugSepOctNovDec
PrimePrimePrimePrimeGoodGood
Sea surface
20°C68°F20°C68°F20°C68°F21°C70°F22°C72°F23°C73°F
Daytime high
21°C70°F23°C73°F25°C77°F27°C81°F29°C84°F30°C86°F
Rain
39 mm1.5 in48 mm1.9 in37 mm1.5 in90 mm3.5 in121 mm4.8 in146 mm5.7 in

2011–2025 averages. Sea surface: NOAA Coral Reef Watch, measured at the surface, so deeper water can run colder. Daytime high and rain: NASA POWER.

Grey nurse numbers peak Jun–Nov; the Eastern Australian Current brings the warmest, clearest water Jan–Apr.

Best months: June, July, August, September, October

South West Rocks water temperature and weather by month

The sea surface runs from 20 °C (68 °F) in August to 26 °C (79 °F) in February. It is 24 °C (75 °F) or warmer from January to April. Most rain falls from November to March, peaking at about 230 mm (9.1 in) in March; July to September are the driest. Daytime highs reach 30 °C (86 °F) in January and drop to 21 °C (70 °F) in July. Below the surface the water can drop to about 17 °C (63 °F), so pack a 7 mm suit with a hood, or a semi-dry.

Dive types & marine life

Grey nurse shark numbers build from around June and hold through spring before thinning over summer. Wobbegongs, turtles, stingrays and eagle rays are there all year, black cod sit back under the ledges, and nudibranchs and octopus work the walls. The warmest, clearest water lands in the first months of the year, when tropical strays ride down on the current.

  • Cave & cavern
  • Reef
  • Wall
  • Drift
  • Night
  • Sand tiger sharks
  • Wobbegongs
  • Sea turtles
  • Stingrays
  • Reef fish swarms
  • Octopus & cuttlefish
  • Nudibranchs
  • Groupers
  • Eagle rays

Best dive sites in South West Rocks — Fish Rock

A tennis-court-sized reef with resident green turtles

5–10 mintermediate

The southernmost reef where plate coral grows this thickly

6–20 mintermediate

Black coral on the gutter walls, then semi-trailer-sized boulders

to 32 madvanced

Cave & cavern

One of the largest ocean caverns in the Southern Hemisphere

to 24 madvanced

Eagle rays over the two narrow gutters at the southern tip

6–18 mintermediate

A deep drift to 40 m with groper out of the shadows

30–40 madvanced

Flat rock at 14 m where hammerheads patrol in summer

14 mintermediate

A 1950 motor lighter upright at 87 m, found only in 2009

to 87 madvanced

Grey nurse sharks cruising a sand gutter at 24 m

to 24 madvanced

Pinnacle

Twin peaks at 8 m over a gutter full of grey nurse sharks

8–35 madvanced

A 40 m sponge wall with groper, black cod and cruising whalers

to 40 madvanced
  • The Aquarium

    Shallow boulder field at 12 m, dense with fish and easy in swell.

How to get to South West Rocks — Fish Rock

South West Rocks is on the New South Wales mid-north coast, roughly halfway between Sydney and Brisbane by road. Flying into Port Macquarie or Coffs Harbour and driving an hour or two is quicker. The town itself is the base, with shops, beds and the boat ramp minutes apart, and Fish Rock is reached only by day boat.

Photos from South West Rocks — Fish Rock

  • Richard Ling · CC BY-SA 2.0

  • Richard Ling · CC BY-SA 2.0

Dive videos

Diving South West Rocks - Fish Rock Cave and Grey Nurse Sharks · Damien Wittmack - Underwater Video on YouTube

Diving Fish Rock Cave at South West Rocks with near perfect conditions. 50+ Sharks! · Pursue The Adventure on YouTube

Photo credits

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