Studies on the acquisition of Spanish as a first language do not agree on the patterns and factors relevant for coda development. In order to shed light on the questions involved, a longitudinal study of coda development in Northern European Spanish was carried out to explore the relationship between accuracy, markedness and frequency. The study analysed 8517 intended codas produced by two children from age 1;7 to 2;7. The main contribution of this study comes from the analysis of substitutions. The children produced more codas and more accurate codas in stressed syllables, particularly in word-final position before the age of 2, but after 2 years old their coda production was target-like in stressed medial position. They substituted phones in unstressed and in word-final position. It is argued that the most salient and frequent characteristics of Spanish syllable structure enhance coda development in the early years. Only after the establishment of the syllable structure do children focus on segmental quality, which results in target-like acquisition of Spanish codas following markedness predictions. Substitution patterns are independent of syllable structure: sonorant codas are substituted with a sonorant, and obstruents with an obstruent regardless of stress and position.