Fish Rock is Bicheno's best-known shore dive: a large granite spire standing about 75 m offshore at the edge of the reef in front of the breakwater, split almost in two and with a large cavern on its shore side. The Combined Clubs guide describes an 8 m boulder split through its centre surrounded by weedy reef, and the Marine Life Network guide rates it as an excellent day and night dive with a safe breakwater entry and exit.

The weed and cray-weed beds around the rock are the place to look for pot-bellied seahorses and weedy seadragons, and cuttlefish, octopus and southern calamari are frequent, especially at night. Mackerel, trumpeter and banded morwong school around the spire, while tunicates, sponges and sea spiders cover the rock faces. The maximum depth is about 15 m, and most of the dive is spent at 6-12 m.

Because it can be reached from the shore in a short swim, Fish Rock is a common training site and the standard way to finish a Bicheno trip once the boats are packed away. It is also one of the few places in the area that can be dived independently without a boat. The rock sits at the edge of the Gulch approach, however, so divers should tow a flag or stay deep enough to avoid boats.

Fish Rock and the adjoining Waubs Bay dive (which follows the sand edge west to the split bommie known as The Rock) are often combined on one long dive. Together they are the most accessible diving on the Tasmanian east coast and a good way to see the east coast's seahorses and seadragons without leaving the shore.

Bicheno is on the Tasman Highway (A3), about 2 hr 15 min from Hobart and 2 hr from Launceston. From the main highway intersection head north along Burgess Street beside the park, then turn right towards the old harbour and the Gulch; park near the concrete breakwater, a few metres from the water. Kit up at the car, walk a few metres to the breakwater and enter from its inside edge, where the rock slopes gently into the water and a railing has been installed.

Surface-swim about 75 m out to the spire before descending. Exit the same way. Boats from the Gulch can also drop divers here in a minute or two.

Waubs Bay and the breakwater area are sheltered from southerly swell and from westerly winds, which blow offshore, so they are the fallback when the outer sites are rough. Easterly and north-easterly swell rolls straight into the bay and makes entry and exit over the rocks hazardous, and the afternoon NE sea breeze in summer chops up the surface. Visibility drops after big southerly blows and heavy rain.

Fish Rock is exposed to easterly swell and to boat wash from the Gulch; it is best on a calm morning or at night with a westerly blowing.

Surface-swim out from the breakwater to the spire, descend and circle it at 8-15 m, looking into the split and the cavern on the shore side. Search the weed on the return swim for seahorses and seadragons, then swim back underwater at 4-6 m along the reef edge to the breakwater exit.

Independent shore dive; historically guided by Bicheno Dive Centre (status unconfirmed - reported closed). Club groups (Tas Uni Dive Club, TSDC, Leven Scuba Club, Combined Clubs Weekend) shore-dive here on Bicheno weekends, usually on the last afternoon.