Stragglers Rocks are the closest offshore reef to Fremantle: a group of visible rocks with limestone reef around them, about 4 nautical miles west of the harbour entrance. They mark the edge of the Five Fathom Bank between Fremantle and Rottnest and are surrounded by wrecks, including the Ulidia inside the reef, two scuttled dredges to the west and the Zedora on the Mewstones to the south.

The Marine Life Network describes depths from the shallows to 12 m, with the best diving on the exposed seaward side, and notes that the reef is often used as a second dive. The limestone is covered in kelp and red algae, with ledges, gutters and overhangs. Buffalo bream, sweep, wrasse, herring cale, leatherjackets and bullseyes are common, western rock lobster live in the crevices, and wobbegongs rest under ledges. Visibility is usually better than inshore sites.

The reef needs calm weather, but its short distance from the ramps makes it useful when Rottnest is too rough or time is short. It suits Open Water divers from boats and can be combined with any of the nearby wrecks for a two-dive morning.

Detailed site information is limited, so this is a general record for the reef. Check the chart for the rocks and breaking water, and anchor well clear.

Because the reef is close to the busy route between Fremantle and Rottnest, fly the dive flag, keep a lookout on the boat and use a surface marker buoy when ascending away from the anchor. The reef is at its best after several days of easterly weather, when visibility can exceed 10 m.

Launch at Woodman Point, Leeuwin Boat Ramp (East Fremantle) or the Fremantle harbour ramps and run west across Gage Roads to the visible Stragglers Rocks, about 20 minutes away. Anchor in sand on the sheltered side of the reef. The best diving is on the exposed seaward (western) side, so choose a calm day and keep a crew member on the boat.

Needs calm weather: the seaward side, where the best diving is, faces the open ocean between Rottnest and Garden Island. Swell over 1 m breaks around the rocks. Dive in the morning before the south-westerly sea breeze.

North-westerly winter winds close the site. Swan River outflow after heavy rain can reduce visibility for a few days.

Anchor on the lee side, swim round to the seaward side and follow the reef edge at 8–12 m, exploring ledges and gutters, then return along the reef top.

Used by Fremantle-based operators and clubs as a second dive or bad-weather alternative to Rottnest; private boats.