Hybrids between Crassostrea hongkongensis and Crassostrea ariakensis were produced to evaluate their aquaculture potential in northern China. Fertilization success was asymmetrical; C. hongkongensis eggs can be fertilized by C. ariakensis sperm, but not vice versa. Molecular genetics analysis revealed that hybrid progeny were true hybrids. Larval growth of hybrids was intermediate between C. hongkongensis and C. ariakensis, whereas larval survival in hybrid families ranged from 0.3–37%. The progeny of C. hongkongensis did not survive during an outdoor overwinter phase, whereas hybrids and C. ariakensis showed similar survival rates (>72%). Mean shell height of hybrid adults at day 360 was 54% larger than that of C. hongkongensis adults, and was 25% larger than that of C. ariakensis adults. Morphology of the hybrid adult was similar to that of C. hongkongensis. On the basis of high overwinter survival and faster growth than either parental species, we suggest that the hybrid between C. hongkongensis and C. ariakensis may substitute for C. hongkongensis as a cultured species in northern China.