Turn indicators and roundabouts

Rule: When joining or continuing in a roundabout, give a “right” indication. When leaving, give a “left” indication.

Traffic Logic: You are indicating whether you are moving into the stream (right) or out of it (left). Giving a left indication just as you join the roundabout is wrong, unless you are turning left and exiting immediately after joining.

As mentioned here, the indicator is for intention, not whatever physical direction the road happens to take.