In this paper, we derive the dispersion relation for waves within ice‐covered waters from the Sentinel‐1 Interferometric Wide swath mode by using an innovative new implementation of the method proposed by Johnsen and Collard (2009). We apply this method to the spatial burst overlap area that is present due to the terrain observations with progressive scans (TOPS) technique. The advantage of this implementation is the use of a larger time separation between subsequent images that results in a less noisy and higher quality imaginary spectrum, which allows us to obtain spatiotemporal information of the dispersion relation. We studied seven wave events in the Barents Sea, where we have accompanying in situ data of sea currents and sea ice draft, available from the Barents Sea Metocean and Ice Network (BaSMIN) measurement programme. Having simultaneous data on the currents is a significant improvement over previous studies and allows us to quantify these data's influence on the dispersion relation. The derived dispersion relation from Sentinel‐1 is derived for long waves propagating through icy waters (peak wavelengths 100‐350 m) and it does not deviate from the theoretical open‐water dispersion relation. At present, however, the spatial resolution of Synthetic Aperture Radar data is too coarse and does not enable the study of the dispersion relation for short waves within sea ice.