Background: Spelling acquisition requires the assimilation of the regularities of the writing system, but these regularities may differ between the native and a foreign language. English spelling acquisition is a challenge for Spanish-speaking children due to differences in the orthographic systems. The aim of this study was to examine to what extent Spanish-speaking children use sub-lexical and lexical information when spelling in English as a foreign language (EFL), and whether this varies across grades. Methods: To achieve this, we administered a spelling-to-dictation task of monosyllabic words to children 9 to 11 years old. Spelling accuracy, written latencies, and writing durations were analysed as a function of phonology-to-orthography consistency, lexical frequency, word length, and the semantic knowledge that the children have of the words. Results: Results showed differences between grades, with word length only influencing younger children. Lexical frequency, consistency, and semantic knowledge facilitated performance in older children. The cumulative exposure to English may lead to an improvement in spelling due to vocabulary growth and increased sensitivity to new spelling patterns and regularities. Such development occurs despite differences between the orthographies of the native and foreign language and even in the absence of explicit instruction in EFL spelling. Conclusions: Semantic information about words helps spelling retrieval during writing in EFL. Spanish-speaking children develop sensitivity to English orthography and spelling patterns, evident in the older group of children.