Section 158 of the Government of Wales Act 2006 (GOWA 2006) provides that 'Wales' includes the sea adjacent to Wales as far out as 12 nautical miles measured from coastal baselines (known as the 'Inshore Region'). Accordingly, within the Inshore Region the National Assembly for Wales has legislative competence, subject to section 108A of GOWA 2006.
The Welsh Ministers exercise a wide range of functions in relation to both the Inshore Region and Offshore Region. In broad terms the Offshore Region is any area beyond the Inshore Region but the precise extent will vary depending on the regime. Some of the more important functions and their area of application include (this is not an exhaustive list):