Spatial information is limited for artisanal fisheries management and almost entirely absent for migrant fishers. Here, we addressed this data gap for East African migrant fishers via participatory mapping methods. We worked with 14 migrant fishing vessels operating from four fish landing sites in Kenya. We monitored individual vessels using GPS tracking to produce fishing ground intensity maps. We then generated fishing preference maps via focus group discussions. The fishing intensity maps provided high-resolution spatial information on fishing activities, whereas the fishing preference maps identified preferred fishing grounds. These two techniques generally showed high agreement. By further integrating these two fisher coproduced maps with supplemental vessel logbook data, it is clear that any spatial management measures would most affect migrant fishers using ringnets, hook and line, and cast nets gear. Our successful application of low-technology participatory mapping techniques to provide geospatial fisheries data have broad application to data poor fisheries worldwide.