Spikey Beach, beside the convict-built Spiky Bridge south of Swansea, is rated 6 out of 10 by the Marine Life Network guide. Two beaches are separated by a rocky headland, and the reef around it is frequently dived, with wrasse, leatherjackets and a variety of reef fish in 2-6 m.

The guide notes the site avoids the fishing nets that complicate boat access elsewhere in the bay. With easy parking at a day-use reserve and a gentle beach entry, it is one of the most convenient shore dives on the west side of Great Oyster Bay.

The western shore of Great Oyster Bay around Swansea is a quiet stretch of coast known more for beaches, vineyards and the convict-built Spiky Bridge than for diving. Water inside the bay is often calmer but less clear than on the ocean coast, and several good sites are reached across private farmland, so local permission is part of the planning.

Practical points apply to all of these shore sites. There is no dive shop, air station or hire between Hobart and Bicheno, so divers bring filled cylinders and all equipment. Mobile coverage is generally good along the highway but patchy at the water's edge, and the nearest hyperbaric chamber is the Royal Hobart Hospital, one to two hours' drive away, so conservative profiles and oxygen in the car are sensible. Water temperatures range from about 11 °C in winter to 17-18 °C in late summer, so a 7 mm wetsuit with hood or a drysuit is standard year-round.

Spikey Beach is beside the Tasman Highway about 7 km south of Swansea, next to the historic Spiky Bridge (1843). Park in the Spiky Beach day-use reserve and walk a short distance to the beaches; enter from the beach beside the central rocky headland. From Hobart the route is the Tasman Highway (A3) via Sorell and Buckland; allow extra time on weekends when the road is busy with holiday traffic.

Kit up at the car and check the entry and exit before committing, since the rocks are slippery at low tide.

Spikey Beach faces east into Great Oyster Bay; it is calm in westerlies but gets choppy in the summer NE sea breeze and in southerly winds. Mornings are usually calmest in summer, before the north-easterly sea breeze builds, and a day or two of westerly weather gives the clearest water. Visibility of 5-10 m is normal.

Enter from one beach and follow the rocky headland around to the other beach at 2-6 m, then return or exit on the second beach. Turn at a third of gas to allow for the swim back and a possibly harder exit, finish with a 3-minute safety stop at about 5 m if the depth allows, and exit where you entered unless an alternative exit has been checked beforehand.

No regular operator. Shore dives used by Hobart clubs (Tasmanian Scuba Diving Club, Tas Uni Dive Club) and self-sufficient divers; Hobart shops occasionally run east-coast weekends.