Various modeling studies have examined the climatic effects of either the Central American Seaway or the Indonesian seaway. The co‐existence of these two tropical seaways may have a greater influence than the existence of a single seaway. Although the dual seaway situation is closer to that reconstructed during Miocene/Pliocene, relevant studies remain scarce. Here, we investigate the co‐effects of dual tropical seaway changes on the Pacific circulation through a set of sensitivity experiments. Our results show that the combined shallow opening of tropical seaways can generate an active Pacific meridional overturning circulation and maintain strong upwelling conditions along the equatorial Pacific, which may have helped favor a “biogenic bloom” during the late Miocene and early Pliocene. Moreover, the logically successive closure of the tropical seaways can provide patterns of zonal sea surface temperature gradients that are similar to those recorded in the equatorial Pacific from the late Miocene to the Pliocene. Plain Language Summary During the late Miocene and the Pliocene, changes in the Central American and the Indonesian seaways geometry are very important for ocean circulation and global climate. Various modelling studies have examined the separate effects of these two tropical seaways, especially their link to the onset of the Northern Hemisphere ice sheets through changes in the Atlantic meridional overturning circulation and associated heat and moisture transport. Although the existence of dual tropical seaways is closer to the reality, there are very scarce modelling studies exploring the co‐effects of dual tropical seaway changes, especially on the Pacific ocean circulation. Here we provide the results of modelling study on this issue. Our results show that the combined shallow opening of tropical ways can generate an active Pacific meridional overturning circulation (i.e., absent in modern conditions) by which the meridional and zonal sea surface temperature gradient in the Pacific largely reduce. In contrast, a deeper opening of tropical seaways can not produce these changes in the Pacific ocean circulation. This study provides insights into and a better understanding of the role of tropical seaways in shaping the Pacific climate and highlights the importance of the sill depth of each seaway. Key Points The co‐effects of opening of two tropical seaways on the Pacific circulation are investigated with climate model Shallow opening of tropical seaways can generate an active Pacific meridional overturning circulation, whilst a deeper condition can not The stepwise closure of the tropical seaways can provide similar‐to‐record patterns of zonal sea surface temperature gradients