Piracy is both an historical and a contemporary problem. In the past decade it has also proven to be a legal problem. Under international law, many of the attacks against ships that are commonly characterized as piracy actually fall outside of the legal definition of piracy. This has widespread implications for States seeking to undertake law enforcement activities to combat attacks and address maritime security concerns in order to establish a safe maritime environment for shipping and seafarers. This chapter examines some of the challenges presented by the current legal framework for ‘piracy’ and ‘armed robbery against ships’. It first sets out the applicable international law and distinguishes between the two terms. It then provides an overview of piracy and armed robbery against ships in two regions of the world that have been subject to a large number of attacks in the past decade, Southeast Asia and Somalia.