Great for swimming from November to April, care should be take in the low season (May-October) when there can be strong undertows. The local restaurants just above the beach make a great place to relax with a sundowner.
Further south is Ya Nui, a sandy cove that attracts snorkelers and divers. Another out-of-the way spot nearby is the tiny beach of Ao Sane, a great spot for snorkeling, reached by taking the road that starts at The Royal Phuket Yacht Club car park.
Credit : http://www.phuket.com/island/beaches_nai_harn.htm#