Abstract: The present invention concerns a scanning apparatus (1) and method for scanning a sub-sea structure (2). The apparatus comprises a scanner array (3) and a guide for defining a direction of travel of the scanner array from a start position to a finish position. A drive means (10) is provided for moving the scanner array from the start position to the finish position and the array comprises a plurality of sensors arranged in a common plane that extends substantially orthogonally to the guide direction of travel.