This data was gathered as part of the MESH SW Approaches canyons survey; a collaborative survey involving the Joint Nature Conservation Committee, the Marine Institute, the British Geological Survey and the University of Plymouth. Defra Natural Environment Group Science Division (CRO 361) made a significant contribution to this work. The work contributed to the MESH project that received European Regional Development Funding through the INTERREG IIIb Community Initiative. The aims of the survey were to acquire high resolution multibeam, sub-bottom profiler and seabed imagery data in the SW Approaches area, located approximately 320km southwest of Land's End. The cruise not only mapped the variable morphology of the area, but also investigated the biological communities within the canyon system for the assessment of a potential SAC under the EC Habitats Directive. The cruise also tested the application of the survey standards and protocols developed under the MESH project. The cruise was the first thorough test for the recently completed MESH Guidance Framework, providing a 'proof of concept' from planning to completion.