A collection of raw format seafloor visual images acquired during a survey within the Greater Haig Fras Marine Conservation Zone (MCZ), central Celtic Sea, in 2012. This was the first in a series of surveys to be conducted in this location. A camera system mounted on the autonomous underwater vehicle (AUV) Autosub6000 was deployed during RRS Discovery cruise 377/8 (D377/8), and images were collected from four 4.7 km transect lines. The raw images are provided in this collection, available on request. The images are provided in a raw format unique to the Grasshopper 2 camera system. The aim of the survey was to undertake high-resolution acoustic seabed mapping and visual imagery in a Marine Protected Area, in order to highlight the capability of AUV technology for offshore seabed mapping and benthic assemblage assessment. The work was initially undertaken as part of a Defra-funded project "Investigating the feasibility of utilizing AUV and Glider technology for mapping and monitoring of the UK MPA network (MB0118)", Case study 2: Shallow-water AUV mapping off SW UK (https://nora.nerc.ac.uk/id/eprint/500733/), and the Natural Environment Research Council (NERC) funded Autonomous Ecological Surveying of the Abyss project (NE/H021787/1), involving scientists from the National Oceanography Centre (NOC), UK. Other supporting datasets available on request include AUV-based multibeam bathymetry, sidescan sonar and CTD data.