Background Although similar standards exist internationally to select beach lifeguards (BLGs), these are generally not based on a task analysis. To reduce the likelihood of drowning, a BLG should reach a casualty within 3.5 min (210 s). Aim To quantify the physical demands of the most critical generic tasks undertaken by BLGs. Methods A survey of 91 BLGs identified sea swimming while towing a casualty, board paddling with a casualty, and casualty handling as the most demanding activities. Performance during beach running (200 m), swimming in the sea (200 m), board paddling in the sea (400 m), swimming in a pool (200 m freestyle and 25 m underwater with 25 m return) and simulated casualty handling were measured. Results The median area at sea patrolled by paddling and swimming was 400 m. The mean 200-m sea swim time was 3.1 min or 188 s (SD = 46 s) and 95% of the BLGs were able to swim 200 m in 3.5 min (n = 22). The mean time to paddle 400 m was 3.8 min or 226 s (SD = 35 s) and 30% of the BLGs were able to paddle 400 m in 3.5 min (n = 23). The 5th percentile paddling speed was 1.38 m/s, therefore, 95% of the BLGs tested should be able to paddle 289 m in 3.5 min. Conclusions If only a rescue board is available, the area out to sea patrolled by a lifeguard should be reduced from 400 m to 300 m.