Ottawa is typically 5 hours behind London. When it's 5:00 PM in London, it's 12:00 PM (noon) in Ottawa. Both cities observe daylight saving time, but they switch on slightly different schedules.
During most of the year, the difference is 5 hours. During the brief periods when North American and UK DST schedules don't align, the difference can be 4 or 6 hours.
Optimal meeting window: 9:00 AM - 12:00 PM Ottawa time (2:00 PM - 5:00 PM London). Morning Ottawa catches afternoon London before end of business.
As the capital cities of two Commonwealth nations, Ottawa and London maintain strong diplomatic ties. The British High Commission in Ottawa is among the UK's largest diplomatic missions.