Hooded Plovers Charadrius rubricollis breed on ocean beaches in southern Australia. Off-road vehicles have access to many South Australian beaches and may affect Hooded Plovers in two ways: (1) by interfering with breeding behaviour, and/or (2) by running over nests. In the Coorong region, Hooded Plovers usually nested on the ocean beach, above high tide mark and close to the base of the frontal dunes. Most nests were within 6 m of the base of the foredune. Measurements of the density of vehicle tracks across the beach indicated that over 20% of the beach was covered by tracks, with the maximum density of tracks occurring 6 m from the base of the foredune. Tie budgets indicated that Hooded Plovers incubated eggs for 87% of the day. Passing vehicles did not cause a reduction in nest attentiveness. The potential rates at which nests were runover was measured by deploying painted pigeon eggs in artificial nests. On average 6% of these nests were runover per day. This rate is equivalent to 81% of the nests on beaches being runover during the incubation period. Thus, the use of off-road vehicles on ocean beaches potentially reduces the reproductive output of Hooded Plovers.