Located in Waterloo, Iowa, the Waterloo Diamonds was a baseball team that formed in 1989 and lasted until 1993. A member of the Midwest League, they were affiliated with two teams in 1989-the Baltimore Orioles and San Diego Padres and the franchise was a descendant of the Waterloo Hawks . From 1990 to 1993, they were affiliated solely with the Padres. Their stadium was Riverfront Stadium.
(from Baseball Reference)