The best times of the day to trade in FX are the points where the main sessions overlap and business moves from one region to another. This happens first thing in the morning GMT, as Asian markets wind down for the day as London opens for business, and then again mid-afternoon London time, as US markets become active and London trading heads towards the close. The handover from the US to Asian FX centres later in the day is probably the least liquid of the three overlaps.