John Frank Cadman (born 27 March 1934) is a former English cricketer and field hockey player. Cadman was a right-handed batsman who bowled right-arm fast. He was born in Colchester, Essex. Cadman played field hockey for Essex, England and Great Britain, who he represented in the 1964 Olympic Games. As a cricketer, Cadman played 2 Minor Counties Championship matches for Suffolk in 1965, against Norfolk and the Nottinghamshire Second XI. He made his only List A appearance for Suffolk the following season against Kent in the Gillette Cup. In this match, he bowled 4 wicket-less overs and with the bat he scored 7 runs, before being dismissed by Stuart Leary.