Just over the ferry at Sandbanks is one of the best beaches in the UK, the three mile long, dune-backed Studland beach. Part of a Nature Reserve this huge stretch of sand is wonderfully scenic and natural, with shallow waters that warm up quickly and acres of rolling dunes that make a superb play pen enjoyed by kids, nudists and gays (different zones! ), although some of the latter can be less-than subtle.
Get there by car/bus across the old-fashioned chain ferry at Poole Harbour entrance (car parking is available at both ends of Shell Bay/Studland beach if you’re early enough or out of season) or bus to the ferry and walk across. n. b. Parking on the Sandbanks side is nearly impossible in season.