Diana Nyad was 18 hours into her trek from Havana to the Florida Keys early Sunday morning, and things are going swimmingly.

"This is the first time we've ever reached international waters without a crisis," her handler Bonnie Stoll was quoted as saying ondiananyad.com, which is blogging Nyad's attempt.

Nyad is attempting to become the first person to swim the 103 miles without the benefits of a shark cage, flippers or wet suit.

It's the fifth try for the 64-year-old - and she has said it will be her last.