GaAs(111)A and (111)B static surface phase maps have been generated under a variety of substrate temperature and incident As4 flux conditions ranging from, respectively, 400–700 °C, and from 1×1014 to 1×1016 molecules cm−2 s−1. For the case of GaAs(111)A only a (2×2) reconstruction was observed. However, four GaAs(111)B surface reconstructions were identified below a critical As4 flux of JcAs4≂5×1015 molecules cm−2 s−1, viz.: (2×2); (1×1)LT; (√19×√19); and, (1×1)HT. Above JcAs4 the (√19×√19) surface phase was quenched, such that the (1×1)LT and (1×1)HT structures merged to form a single (1×1) phase. The transitions to and from each of these surface phases were found to be reversible, occurring at very specific substrate temperatures for a given incident As4 flux. The activation energies (ϵA) characterizing the reversible surface phase transitions were measured and compared with those on the GaAs(100) surface.