Who sings Puff the magic dragon who lived by sea?

The song "Puff the Magic Dragon" was written by Peter Yarrow and Leonard Lipton, and is most famously associated with singer-songwriter Peter, Paul and Mary. Released in 1963, it tells the story of a boy and his imaginary dragon friend named Puff. The first line of the song begins with "Once upon a time, in a kingdom of our own..."