Spatial distribution of fishing effort is increasingly recognised as an important consideration for fisheries management, as it can affect trends in catch rates, and be incorporated into planning of spatial management tools like marine protected areas (MPAs). One hundred and ninety-eight household questionnaires provided a coarse indication of effort distribution of artisanal lobster fishers around the Corn Islands, and 32 semi-structured interviews with skippers were used to map individual fishing sites and describe the operating costs and revenues of typical dive and trap-fishing operations. Artisanal fisheries had ranges of up to 50 km, and had moved significantly offshore within the previous 10 years. At the scale of a 5 × 5 min latitude/longitude grid, trap fishing effort was highly aggregated (dispersion coefficient = 3.5), while diving had a regular dispersion (d.c. = 0.1). Descriptions of catch composition at each site showed a clear spatial pattern in the distribution of two locally recognised types of lobster, potentially indicating local stock structures. Economic information was summarised into balance sheets for typical fishers and suggested that fuel accounted for about 52 and 37% of the operating costs of dive and trap fishing captains, respectively. Qualitative questions highlighted trap theft, adoption of geographical positioning system (GPS) technology and fuel costs as major factors affecting spatial behaviour.