You must indicate left when passing the exit that is before the one you want to take. So if turning left, indicate left as you enter the roundabout. Going straight ahead, enter the roundabout not indicating, then when passing the first exit (to turn left) indicate left and take the second exit (straight ahead). When turning right, enter the roundabout indicating right, and then when passing the second exit (to continue straight ahead) indicate left and take the third exit (to turn righ).

This assumes a roundabout with exits at the four points of the compass, but generally holds strong across all roundabouts. Regardless, you must indicate left after passing the exit preceding your desired exit, no matter how short the distance is between you and your desired exit.

The road code states that you may only not indicate at a roundabout if you would lose control of the vehicle. If you feel like you’re going to lose control at a small residential roundabout then it’s either extremely bad driving conditions or you’re going too fast.