The present study analyses written narratives of 60 Portuguese-German bilingual children between 8 and 15 years living in Switzerland, in both their languages. Portuguese is the children’s heritage language (HL) and German the environmental language. The analysis focusses on the children’s lexical, morphological and structural knowledge in the verb domain (verb types, agreement morphology, verbal tense, word order within the VP, orthography) and aims to determine the role of language dominance, general proficiency, current age and age of onset of bilingualism (AoO) in bilingual language acquisition at later stages of development (i.e., at school-age). The results show that the bilingual children display stable syntactic and morphological knowledge in both their languages. Lexical knowledge is positively correlated with age and proficiency. Morphological and syntactic deviations are residual in both languages and not correlated with AoO. No effects of cross-linguistic influence are observed. We only find performance differences between the Portuguese and the German corpus at the level of orthography. We conclude that in the analysed age span children have received enough exposure to both languages to develop stable morphological and syntactic knowledge, at least in the verb domain.