Where is best place to live for someone in mid-twentys - Adelaide, Yeppoon, Hervey bay, Townsville?

Got job offers in these places and just wondering what would be people's opinion on which one to go for. I am into the outdoors - would like to do more scuba diving, snorkeling and surfing as part of a club. I will be moving to Australia alone in August so I'd like to go somewhere that I can make new friends with similar age to myself and be part of the new community.