In implementing the pan-European Single Sky, the European ATM community needs regular and timely plans and reports on what has been achieved and what still needs to be done. The European ATM Master Plan (MP) Level 3 Implementation Report consolidates the implementation progress reports produced by individual stakeholders on the implementation of those commonly agreed actions which ECAC States have to take in the SESAR context. These actions are presented in the form of “Implementation Objectives” that set out the operational, technical and institutional improvements that have to be applied to the European ATM network to meet the performance requirements for the key ATM performance areas defined in the MP Level 1 – safety, capacity, operational efficiency, cost efficiency, environment and security. The 2015 MP Level 3 Implementation Report was developed in close cooperation with the SESAR Joint Undertaking and SESAR partners. It looks at progress made on achieving the 41 implementation objectives defined in the 2015 Master Plan Level 3 Implementation Plan; most of them are directly related to SESAR functionalities, including the PCP (Pilot Common Project) components. A few implementation objectives are pre-SESAR; these either have to be achieved on a network level - they form part of the foundation on which SESAR is built - or they are related to interoperability. There are also a few implementation objectives related to SES legislation.