A method and apparatus for Round Trip Delay KPI Monitoring in a live network using a user plane probe session is disclosed for measuring round trip delays in a manner that allows latency to be apportioned to network elements. The method and apparatus for Round Trip Delay KPI Monitoring in a live network using a user plane probe session includes transmitting a loopback packet containing a probe session indicator and capturing timestamps of arrival and departure times at each network element traversed by the loopback packet, and then transmitting the timestamps to a Network Management System.