Trading sessions are periods of time when banks are actively trading. As is well-known, Forex's working hours are unlimited, and it functions round the clock. Sessions come one after another, or partially superimpose on one another, giving traders the possibility to trade whenever convenient to them.

Knowing the schedule of trading sessions on the Forex market is also useful because currencies behave differently according to different trading sessions. For instance, if we take a less active period after New York closes and before Tokyo opens, Sydney will be open for trading but with more modest activity than the three major sessions (London, US, Tokyo). Consequently, less activity means less financial opportunity. If you want to trade currency pairs like EUR/USO, GBP/ USD, or USD/CHF you will find more activity when both Europe and the United States are active.