Our understanding of ocean circulation to date still bears many unanswered questions. Despite the development of a variety of methods for observing upper ocean current velocity at different scales, our knowledge of this subject has yet to be significantly improved. Historically, the drift of vessels led to the discovery of the oceanic surface current. The Automatic Identification System (AIS), originally intended to avoid collision in maritime traffic, contains the necessary information to retrieve vessel drift due to the surface current. Thus, the AIS data can be processed to derive sea-surface current components for any region in which there is maritime traffic. A dedicated inversion scheme has recently been theoretically formulated and implemented. In this study, we report the preliminary results obtained during an experimental campaign conducted aboard the oceanographic vessel Atalante, in the strait of Gibraltar, in October 2020. A map of oceanic circulation was calculated using the drift of all vessels emitting AIS messages within the strait and validation was achieved with the help of an Acoustic Doppler current profiler (ADCP) aboard the Atalante.