The 2004 British Formula 3 International Series was the 54th British Formula 3 International Series season. It commenced on 3 April, and ended on 1 October after twenty-four races.
The scoring system was 20-15-12-10-8-6-4-3-2-1 points awarded to the first ten finishers, with one extra point added to the driver who set the fastest lap of the race. If a Class B driver or a guest driver finished among the top finishers, he would not score points for the main championship, and the points would be awarded to the next driver in the standings.
The following teams and drivers were competitors in the 2004 British Formula 3 International Series. The Scholarship class is for older Formula Three cars. Teams in the Invitation class are not series regulars, and do not compete for championship points.
Notes: