This study analyzes the phonological patterns of late -stage consonant clusters (CCs) acquisition, with the aim of exploring the transition between ages 4 and 5. The types of CCs (tautosyllabic/heterosyllabic), 22 of their subtypes, the types of strategies (deletion/substitution), and the types of C1 and C2 singletons (/l/, /r/, /m/, /n/, /s/) were taken into account. The participants were 20 Chilean preschoolers aged 4 and 5 (10/10) with typical language development (TD) monolingual Spanish speakers. The results show differences in the percentages of acquisition by age which indicate that at the age of 5 children are already in a stage of resolution of the CCs phonological patterns. It is noted that from the age of 4, a critical transition occurs that can be observed through the types and subtypes of CCs, strategies and singletons types; its implications in the diagnosis of phonological disorders in relation to phonological awareness and the learning of reading are pointed out.