This dataset consists of image mosaics of submarine canyons off Morocco collected using TOBI side-scan sonar on RV Maria S. Merian cruise MSM32, which occurred between 25 September and 30 October 2013. Imaging was conducted using a TOBI deep tow sidescan sonar, a high-resolution 2D seismic system consisting of a 150m long 88 channel digital streamer and a standard GI-gun. This cruise formed the field component of NERC Discovery Science project ‘How do submarine landslides disintegrate and form long run-out turbidity currents in the deep ocean, and how erosive are these flows?’ The study aimed to generate the first ever field dataset tracing a large-scale submarine landslide and its associated sediment-gravity flow from source-to-sink. This resulting dataset will aim to answer three important science questions: 1) How quickly do large submarine landslides disintegrate into long run-out sediment flows, and how is this process influenced by shape of the slope? 2) How efficiently do landslides remove failed material, i.e. what proportion of landslide debris is deposited on the slope and how much transforms into a flow that is transported distally? 3) How much sediment is incorporated into the flow through seafloor erosion, and where does most of this erosion take place? The Discovery Science project was composed of Standard Grant reference NE/J012955/1 and was led by Professor Russell Barry Wynn (National Oceanography Centre, Science and Technology). Funding ran from 07 June 2013 to 06 June 2014. Data have been received by BODC as raw files from the RRS James Cook and are available on request from BODC enquiries.