Bonner joined Division Two side Oldham Athletic in March 2004 on a deal until the end of the 2003–04 season, becoming Brian Talbot's first signing since being appointed manager. After criticising Cardiff for not triggering the £50,000 bonus payment for matches played, he was rebuffed by Lawrence who commented "I have never heard such nonsense in my life. (He) had a two-year contract shortly after I took over, a deal extraordinarily generous in both length and terms." Bonner had been recommended to Talbot by Lawrence and Cardiff had paid Bonner a £30,000 tax free lump sum to move as Oldham were unable to afford his full wages.