The embryonic epicardium provides a source of multipotent progenitors for cardiac lineages, including pericytes, fibroblasts and smooth muscle cells. However, it remains unclear if the epicardium comprises of heterogeneous progenitors or if epicardial cells are multipotent. Using scRNA-seq, we analysed the expression profile of epicardial and epicardial-derived cells at E15.5 and found no evidence of discrete epicardial sub-compartments. Our findings also support the notion that epicardial fate is specified after epithelial-mesenchymal transition, not pre-determined. Overall design: E15.5 heart tdTOM+ sorted cells labelled with Wt1CreERT2; SMART-Seq2 sequencing of E15.5 heart tdTomato positive sorted cells labelled with tamoxifen induction at E9.5 (1mg) and E11.5 (1mg) of Wt1CreERT2 from 6 pooled C57BL/6 embryos The following additional sample information is provided in the 'associated_metadata15_updated.csv': nGene: number of genes/cell nUMI: number of unique molecular identifiers/cell percent.mito: percentage of mitochondrial genes/cell S.Score: S phase score calculated using Cell Cycle Regression vignette in Seurat G2M.Score: G2M phase score calculated using Cell Cycle Regression vignette in Seurat Phase: cell cycle phase determined by Cell Cycle Regression Vignette in Seurat CC.differences: score calculated using the Alternative Cell Cycle Regression Vignette in Seurat res 0.6/0.8/1/1.2/1.4: Different cluster allocation calculated via FindClusters in Seurat