© 2017 Koninklijke Brill NV, Leiden. In the present study we explored the effect of the tidal hour on the postlarvae abundance of the penaeid white-leg shrimp (Litopenaeus vannamei (Boone, 1931)) in three Mexican Pacific coastal lagoons. Correlation analysis of tidal hour against the hourly variation of the abundance of postlarvae was conducted in three regions of the Mexican Pacific; the system lagoon Huizache-Caimanero LHC, the region of the "Grandes Lagunas" SGL and the "Mar Muerto" Lagoon LMM. Two peaks were found in L. vannamei abundance in the three locations, at 04:00 and 16:00 of tidal hour in LHC and SGL, and 06:00 and 12:00 of tidal hour in LMM. Significant correlations between postlarvae and the tidal hour for the three regions were found. The tidal hour standardizes the time of ebb and flow. It is concluded that tidal hour can be used as cue for shrimp postlarvae immigration to nurseries.