Greenhills Beach is Sydney's only dedicated ocean-facing dog off-leash exercise beach, a wide three-kilometre stretch of golden sand facing directly into the Tasman Sea on the Kurnell peninsula between Cronulla and the Kamay Botany Bay National Park headlands. Unlike the Sydney harbour dog beaches which are usually small and tucked into coves, Greenhills is a proper open-ocean surf beach with consistent rolling swell, beach breaks that suit bodyboarders and casual surfers, and kilometres of uninterrupted sand for long ball-chasing runs. The southern end of the off-leash zone links into the Kurnell sand dune system behind the beach, and the sand flattens out spectacularly at low tide into wide compact sandflats that are perfect for running and long-line fetch games.

Sutherland Shire Council runs a clearly defined seasonal off-leash schedule at Greenhills Beach, with different rules for the winter and summer daylight saving periods. In the cooler months from May through to the end of August – Australian winter – the entire signed three-kilometre off-leash stretch is open to off-leash exercise 24 hours a day, seven days a week, with no time restrictions at all, which is why it is such a favourite with working owners and high-energy dog breeds. In the warmer beachgoing season from September through to the end of April, off-leash access is restricted to the early morning and late afternoon windows only: before 10:00am every day, and again after 4:00pm, so that the central section of beach can be turned over to patrolled family swimming between the red and yellow surf life saving flags during the heat of the day.

The main access point and car park is at the end of Captain Cook Drive via the Greenhills entry road, with a sealed parking area that includes disability accessible spaces, a council toilet block, covered picnic tables with electric barbecues, poo bag dispensers and a water tap for rinsing dogs near the sand dune crossing boardwalk. The surf life saving club patrols the patrolled swimming section on weekends and public holidays from September through April, though the off-leash zones at the extreme northern and southern ends of the beach fall outside the flag area so dogs and owners need to self-supervise swims. A 4 kilometre return on-leash shared cycle path runs along the back of the dunes from the Greenhills car park down through the national park towards the Kurnell village end, ideal for a longer warm-up walk before unclipping the leash once you enter the signed off-leash zone boundaries.