In plain English
What London session means
London is a major center for foreign-exchange dealing, so the term is widely used to describe the period when many European banks, dealers, asset managers, and corporate participants are active. Common session schedules show it beginning in the European morning and extending into the afternoon, but exact displayed hours change with time zones and daylight saving.
Why it matters
For pairs involving the euro, pound, or Swiss franc, activity may be more concentrated while European participants are active. That can affect available liquidity and short-term price movement, but it does not ensure tight spreads or reliable execution. Liquidity can weaken around holidays, market disruptions, and scheduled news releases.
Example
A U.S.-based platform may label its London session as 3:00 a.m. to noon Eastern Time during one part of the year and show different clock hours after daylight-saving changes. The underlying London business day has not shifted by the same amount; the difference comes from changing time-zone offsets.
Quick answers
Common questions
When does the London session start?+
There is no universally binding start time. Many education charts use a London-morning convention, but the answer depends on whether the schedule is stated in UTC, London local time, or your platform’s server time, as well as daylight saving.
Does the London session cover only the United Kingdom?+
No. The label is shorthand for a period centered on London during which European FX activity is substantial. Other European financial centers and global participants can trade at the same time.
Sources