It commenced on 2 April 2005 and ended on 9 October after twenty two races.
The following teams and drivers were competitors in the 2005 British Formula 3 International Series.
Teams in the Invitation class are not series regulars, and do not compete for championship points.
The Spa, Monza, Silverstone and Nürburgring races were held supporting the Le Mans Series.
The remaining rounds supported the British GT Championship.