Don’t be lulled into a false sense of security: the beaches do have perils as well as pleasures. Some are protected by special shark nets, but they don’t keep out stingers such as bluebottles, which can suddenly swamp an entire beach; listen for loudspeaker announcements that will summon you from the water in the event of shark sightings or other dangers. Pacific currents can be very strong indeed – inexperienced swimmers and those with small children would do better sticking to the sheltered harbour beaches or sea pools at the ocean beaches. Ocean beaches are generally patrolled by surf lifesavers during the day between October and April (all year at Bondi): red and yellow flags (generally up from 6am until 6 or 7pm) indicate the safe areas to swim, avoiding dangerous rips and undertows. It’s hard not to be impressed as surfers paddle out on a seething ocean, but don’t follow them unless you’re confident you know what you’re doing. Surf schools can teach the basic skills, surfing etiquette and lingo. You can check daily surf reports on realsurf.com.
The final hazard, despite the apparent cleanliness, is pollution. Monitoring shows that it is nearly always safe to swim at all of Sydney’s beaches – except after storms, when storm water, currents and onshore breezes wash up sewage and other rubbish onto harbour beaches, making them (as signs will indicate) unsuitable for swimming and surfing. To check pollution levels, consult the Beachwatch Bulletin (1800 036 677, environment.nsw.gov.au).