The mechanism underlying the crosstalk between Gαq-coupled bombesin receptor subtype-3 (BRS3) and Gαi-coupled E-prostanoid 3 receptor (EP3) remains unknown. Here, we report that BRS3 and EP3 form dimers in the membrane of living HEK-293T cells. Interestingly, we found that BRS3-EP3 dimers switched to couple Gαs protein upon PGE2 stimulation, which provoked the accumulation of cAMP and enhanced the phosphorylation of P38. Quantitative proteomics analysis revealed that the activation of BRS3-EP3 dimers was associated with cell migration. B16 melanoma cell line, which endogenously expresses BRS3 and EP3, was selected to investigate the function of BRS3-EP3 dimers. Results demonstrated that the presence of BRS3 inhibited the migration of B16 melanoma cells upon PGE2 stimulation using scratch-wound assay. Utilizing inhibitors of Gαs and P38, we found that BRS3 interacted with EP3 and switched to couple Gαs protein, causing P38 phosphorylation to inhibit F-actin rearrangement and ultimately suppresses cell migration. Our study reveals the crosstalk between the orphan receptor BRS3 and EP3, and provides a potential novel target for disease treatment.