Match racing is officiated by umpires on the water who follow the boats and make instant on-course decisions about whether a penalty is given. In 1988, LBYC invited a group of experienced judges and they served as the first umpire team in a major world level match race.

The umpire boat will use yellow and blue flags to indicate which boat has been given a penalty or a green flag if no penalty is given.

When a boat is penalized it must complete a full circle penalty turn. This can be done at any time during the race before the finish line. If one boat has a penalty and the other also gets one before the first has taken theirs then they are cancelled out. If a boat receives three penalties then it is disqualified.

Each pair of boats racing is followed by two umpire boats. If a Skipper thinks a foul against them has occurred he will hold up a flag. The umpire will immediately respond as to whether a foul has occurred.

If the umpire determines there is no foul they will hold up a green and white checkered flag. If there is a foul the umpire will hold up a yellow or blue flag (each boat will have either a yellow or blue flag flying off the back) which indicates that boat has been charged with a penalty and is required to complete a 360 degree turn before crossing the finish line.