The 21 year old New Zealander has joined Swindon for an undisclosed fee on a two 1/2 year deal from fellow Division Two side Barnsley.
Fallon has already played 18 times for Barnsley's first team this season scoring four goals including one against Swindon at Oakwell in September.
The Football League have approved the move, and Fallon could play this weekend against Oldham.