ENDURUNS project aims at the development of an integrated hybrid autonomous unmanned vehicle (AUV) system capable of operating under deep ocean conditions and performing a wide-range of missions, targeting the increase of scientific knowledge as well as industrial capability and performance. The hybrid AUV will be also powered by a hydrogen fuel cell, resulting in extremely higher endurance when compared with conventional commercially available AUVs and gliders. Due to its versatile nature, the ENDURUNS system will be suited to perform scientific missions, such as seabed mapping, profiling, geological and geophysical surveys, commercial missions, such as inspection of infrastructure and assets, mineral and seabed mining exploration missions and public authority missions such as surveillance, search and find missions (e.g. aircraft wreckage), equally well. Therefore, the ENDURUNS system will enable for the first time long endurance missions for a wide variety of high impact deep sea applications.