Entrants began arriving soon after 6am on Saturday at the Waterfall Creek end of Ruby Island Rd for the first event of the morning, the Ruby 10, a 10km swim which began at 7am.
After several laps around Ruby Island, 50-59 year category entrant Donal Barry was the first man to cross the finish line in a time of 2hr 15min 6sec.
The first woman to finish the Ruby 10km swim was 20-29 year category entrant Liana Smith, of Queenstown, in a time of 2hr 44min 45sec.
Even though the water was a chilly 14degC, Ms Smith was one of a handful of entrants who did not wear a wetsuit.
She emerged from the water covered in brown streaks of Lindavia, the algae species responsible for creating lake snow, and said "it could have been worse, it could have been duck itch".
There were 465 entrants who swam in the events, and organisers Eddie Spearing and Jamie Norman said they thought this year’s Ruby swimming event was arguably "the best so far".
Mr Spearing said profits from the event would go to The Touchstone Project, a collaborative community project focused on the Lake Wanaka environment.
Both duck itch (or schistosome cercarial dermatitis) and Lindavia were subjects of research projects being undertaken by Touchstone.
