Small-scale ocean currents are crucial in regulating Earth’s climate, with a significant impact in the distribution of ocean properties. During the Calibration/Validation phase of the Surface Water and Ocean Topography (SWOT) satellite mission, we performed a high-resolution, multi-platform experiment to evaluate SWOT’s ability to resolve small-scale features, focusing on a ~20-25 km-radius anticyclonic eddy in the Western Mediterranean Sea. Underwater glider data identified biconvex isopycnals, classifying the eddy as an intrathermocline feature with a ~3 cm sea level anomaly. Acoustic Doppler Current Profiler (ADCP) data recorded maximum velocities of ~40 cm/s. SWOT successfully captured the sea level signal and geostrophic currents of the eddy, showing notable improvements over conventional altimetry: 33% in sea level representation compared to glider, 61% in horizontal velocity compared to ADCP, and 44% and 10% in velocity magnitude and direction compared to drifter measurements. This study highlights SWOT’s potential in resolving small-scale ocean dynamics.