"Once in a Blue Moon" is the first segment of the forty-sixth episode of Miles from Tomorrowland. It premiered on February 18, 2017 alongside "The Queen Gemma Dilemma", and is the first segment of the sixteenth episode in the second season.
Miles and his Cosmic Explorer friends go rafting on an alien planet to earn a rare holo-badge.
- Justin Felbinger as Miles Callisto
- Fiona Bishop as Loretta Callisto
- Tom Kenny as Leo Callisto
- Olivia Munn as Phoebe Callisto
- Dee Bradley Baker as M.E.R.C.
- Sam Lavagnino as Blodger Blopp
- Issac Ryan Brown as Haruna Kitumba
- Adrian Grenier as Captain Joe
- Grey DeLisle as Stella
- Leo and Joe are revealed to be Cosmic Explorers when they were young.