An 18-year old man gave chase to a would be robber at Portlaoise town park on Tuesday afternoon.
The incident occurred at 3.20pm when the man was entering the park at the New Road entrance, and his wallet was snatched from his hand.
The would be thief is described as being 5 foot 6 and wearing a navy tracksuit.
He dropped the wallet in the ensuing chase, before making his escape.
Anyone with any information is asked to contact Portlaoise Garda Station at 057 86 74100.