The Irish Sea has a singular and resonant place in a shared British and Irish imagination, and the simple question of its power both to connect and to divide has commanded political and cultural attention for centuries. This chapter investigates the cultural history of sea crossings, offering an analysis of their inscription in literature and the visual arts. In the process it describes a phenomenon that is possessed of both highly public and quietly intimate meanings, crossing centuries, countries, and lives in diffuse, extensive, and varied patterns.