In the present study, intraspecific crossing experiments between Chinese (H) and Thai populations (T) of Babylonia areolata were conducted by using a complete diallel design (H, T, TH, and HT). A total of 45 pedigreed families were obtained and cultured under the same environmental conditions. Positive heterosis was observed for many developmental parameters and shell sizes for most stages from juvenile to adult. Hatching and metamorphosis occurred significantly earlier in the hybrid (HT) than in the parent groups and a crossed group (TH). Rate of metamorphosis was also higher in HT than in the other three groups. Heterosis in shell length and body weight of the crossed group (HT) from the nursery and grow-out stage to harvest time was high and significantly different from the H, T, and TH groups. For mortality rate from juvenile to adult, total and average heterosis of the crossed group (TH) was positive and significantly different from H, T, and HT. The results of the present study show that intraspecies crosses can be a potentially useful way to increase the economic traits for B. areolata and thus provide a promising method for genetic improvement of the species as a new aquaculture stock in southern China.