The paper focuses on problems related to modelling the development of maritime economic space. This entirely new issue has emerged from the recent changes in the intensity of use of marine areas. First, the economic significance of maritime space is discussed, followed by a simple model based on maritime spatial rent which aims at explaining the patterns of its development. This model encapsulates the interplay between both market and public choice factors that affect the development of maritime space. The paper also includes a discussion of attempts to obtain a monetary value of maritime spatial rent for key offshore maritime sectors in Poland. The paper concludes with suggestions on further developments in this field.