This dataset details the paternity of progeny from Eschscholzia californica plants introduced to habitats comprising different floral cover. Data was collected in June 2015 at the Hillesden estate, Buckinghamshire, UK. Plants were genotyped at seven microsatellite markers before being introduced across the study site to form experimental arrays. Experimental arrays comprised of three E.californica plants separated by 1m and arranged in a triangular formation. A total of sixteen arrays were introduced across four 100 hectare replicate blocks, each separated by >500m. At the centre of each block, four experimental arrays were placed at 50m intervals along a 150m transect laid symmetrically across the boundary between an established wildflower patch and bare, fallow ground or grazed grassland (two arrays within the florally rich habitat and two arrays within the florally poor habitat). Upon maturation approximately 10 seeds were collected from each plant and genotyped. Fragment analysis was conducted and alleles were scored on Genemarker. Seeds were then manually scored as outcrossed or selfed and paternity was determined using Cervus. The dataset was part of a larger experiment looking at the effect of floral resources on the pollination services to isolated plants. Full details about this dataset can be found at https://doi.org/10.5285/7b721c07-bc38-4815-8669-4675867663d0