An Internationally Designated Area (IDA) is a natural area internationally recognised by a global or regional designation mechanism. Among these, there are 263 areas where different IDAs fully or partially overlap thus carrying double, triple or even quadruple international designations. These areas are named Multi-Internationally Designated Areas (MIDAs) for the purpose of this publication. Following up on Resolution WCC-2012-Res-052 adopted at the IUCN World Conservation Congress (Jeju Island, Republic of Korea, September 2012), this Guidance addresses specific issues related to the management of MIDAs, and includes recommendations for harmonising the management, systematic conservation and sustainable use of these areas aimed at the local, national and international stakeholders of MIDAs.