Honey Hunt, three, and her sister Poppy, 10 months old, were baptised inside Zippo's Circus ring on Hove Lawns on the Sussex seafront.
The service was performed by the Rev Roly Bain, from Bristol, who is a clown - and a Church of England priest.
"All my clowning has some sort of Christian content - and this sort of thing is brilliant," he said.
He added that the big top was just as appropriate a place for a baptism as a church building.
— Red Panda, Juggles for Jesus, Light Reading