Every tuesday at 6:45-7 am ish we do an ocean workout (coached) at Kaimana/San Souci beach. Normally lasts about an hour and we swim about 2500 M with some drills and a lot of socializing. I saw 5 turtles yesterday.
Waikiki Swim club does ocean swims every Sat and Sunday from Ala Moana and Kaimana Beach (not sure what day is what). I think their website is
http://www.waikikiswimclub.org There are always people swimming in Ala Moana (1000 M long beach that is inside a reef so it's protected). As well as at Kaimana Beach (there's a windsock about 200 M from the beach people swim out and back too).