This study provides the first evidence of the evolution of a frontal slick in Lake Geneva, a large, deep lake in western Europe. Our results rely on field measurement, remote sensing data, and three-dimensional numerical modeling. The data presented here comprise: (1) measurements from an autonomous catamaran, including GNSS data, near-surface temperature profiles, weather station, near-surface Acoustic Doppler Current Profilers (ADCP), and RGB images from two onboard cameras, (2) infrared images from a FLIR camera attached to a helium-filled balloon, (3) time-lapse images from a shore-based imaging package provided slanted (non-perpendicular) field of views of the lake surface water, (4) Excitation Emission Matrix (EEM) using a Fluorescence Spectrometer for the Fluorescent Dissolved Organic Matter (FDOM) inside slick/non-slick samples, and (5) results of a 3D numerical simulation provided details of the lake hydrodynamics during the field measurement campaign. The three-dimensional model used in this study is based on the MIT General Circulation Model (MITgcm, http://mitgcm.org/, https://doi.org/10.1029/96JC02775).