It has already taken on 15 local employees and more are expected to join as the business develops.
Early projects taken on by the Doncaster office include civils works for the Tween Bridge onshore windfarm, a development of 22 turbines at nearby Thorne that requires 13km of access track to be upgraded.
The Doncaster office will be formally opened by the local mayor on 5 December.
It will be Breheny’s sixth office. As well as the head office in Ipswich, Breheny also has bases in Huntingdon, Kingswood (near Bicester), Boston in Lincolnshire, and Wrotham Heath in Kent.