The maritime operating environment is one of five recognised by UK Ministry of Defence (MoD) doctrine, the others being Land, Air, Space and Cyberspace. This paper describes the relationship between the maritime and cyber environments and introduces and explores in detail the concept of maritime cyberspace in terms of cyberpower projection. It concludes with methods to identify the components of maritime cyberspace to project maritime cyberpower and cyber seapower with particular emphasis on the need to address the potential cyber vulnerabilities of ship systems.