This document is the second version of the Implementation Plan for the Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) initiative and lays out a vision of how associated observational, modeling, synthesis, and programmatic objectives can be manifested. The document was drafted during an international workshop in Potsdam in July 2015, and further developed during two additional workshops at AWI Potsdam in December 2015 and February 2016. Support for this planning activity has been provided by the IASC-ICARPIII process, the Alfred Wegener Institute Helmholtz Centre for Polar- and Marine Research, and the University of Colorado/ NOAA-ESRL-PSD. This document provides a framework for planning the logistics of the project, developing scientific observing teams, organizing scientific contributions, coordinating the use of resources, and ensuring MOSAiC’s legacy of data and products. A brief overview and summaries of key science questions are provided in Section 1. Section 2 includes an overview of specific observational requirements, while Section 3 describes the coordination and design of specific field assets. Practical logistics plans are outlined in Section 4. Links with current and future satellite programs and model activities are given in Sections 5 and 6. The MOSAiC data management strategy is given in Section 7. Links to other programs are outlined in Section 8. The appendix (Section 9) lists the parameters to be measured and the participating groups.