This dataset contains high-speed video recordings and particle image velocimetry (PIV) analysis results from granular flow experiments performed on an inclined flume with a fixed rough substrate, at the University of Edinburgh. Included are the high-speed videos (.mp4), a Word document outlining the experimental details and analysis methods, and figures displaying key analytical results of vertical velocity and granular temperature profiles. The flows consist of sand particles with a volumetric mean diameter of 875 µm, propagating over a substrate of coarser sand with a mean diameter of 1063 µm. Experimental conditions include varying slope angles (34°–42°) to investigate the influence of inclination on flow dynamics. PIV was used to analyse the videos, generating vertical velocity profiles and granular temperature profiles. Lens distortion was corrected using MATLAB to ensure accurate measurements. This dataset is relevant to those interested in granular flow dynamics, natural hazard modelling (e.g., landslides, pyroclastic density currents), and granular flow industrial applications.