Why do we need a separate treatment of marine and coastal conflict? The marine environment is different to the terrestrial and as such understandings of why conflict occurs over terrestrial resources may not be useful here. This chapter provides some context regarding the environment in which conflict over marine and coastal common resources occurs, considering the ways in which it is quite distinct. It delves into the physical nature of the marine and coastal environment, examines the benefits we obtain from this environment and their ‘common goods’ nature, reviews the different governing conditions that influence management of this environment, and explores its ‘contested spaces’ character.