This issue of the Instrumentation Viewpoint is centered on the 5th International Workshop on Marine Technology – Martech Workshop 2013. The workshop was organized by the Universitat de Girona and the Universitat Politècnica de Catalunya, and took place in Girona on October 9th -11th 2013. The main goal of the workshop was to show the latestinvestigations and exchange of information and points of view on current research in MARine TECHnology. The issue contains the 55 contributions that were presented in the workshop, as extended abstracts,from 10 different topics: Operational Oceanography; Instrumentation, Metrology, Signal processing; Marine sensors, sensor networks; Observatories, remote sensing; Marine Robotics: ROVs, AUVs, ASVs, Gliders; Underwater imaging and communication;Sea floor characterization; Structures and materials; Marine Biology and Aquaculture; and Renewable energies. The technical program was completed with three invited researchers, which gave a tutorial, Christian Ferreira (Marum), and two plenary talks, Stephen D. McPhail (NOC) and Tim Owen (Carrack Measurement Technology).