We studied the large-scale spatial–temporal distribution pattern of the Mediterranean fruit fly, Ceratitis capitata (Wiedemann) (Diptera: Tephritidae) to understand whether long-term dispersal may affect its maintenance in a highly patchy and isolated arid environment. The study area contained few dispersed settlements and agricultural plots covering 3,000 km², ranging from 100 to 900 m in altitude in southern Israel. Due to the arid nature of the study area, no wild hosts existed outside the settlements. Data were collected from three settlements at different altitudes from 1999 to 2002. During 2000, adult flies were monitored throughout the entire area. Data were incorporated into a geographic information system, and weekly spatial distribution charts were produced and analyzed. Our results suggest that, within the study area, C. capitata overwinters in sites <400 m in altitude with abundant winter hosts but not at higher altitudes. In remote settlements and agricultural areas at higher altitudes, flies reappeared every year in midsummer, which can only be explained by annual migration from the lower altitudes. Our results demonstrate that flies migrate at least 50 km, probably over a single generation, before reaching some of the remote havens within the study area. This long-distance migration has far-reaching consequences for maintenance of remote populations and should be taken into consideration for future basic research and applied control practices of C. capitata.