Research on the transmission and maintenance of heritage languages in Europe is largely dominated by studies on family language policy. Examining how and what decisions are made regarding the language of communication within the family provides valuable insights into language ideologies and the identity formation of heritage speakers. This study explores this relationship through the analysis of six bilingual speakers of German and Spanish as a heritage language. Participants completed a questionnaire on their linguistic biography and participated in individual interviews that delved into issues related to their identity. The analysis focuses on their linguistic beliefs, home language practices, perceptions of their Spanish-speaking parents’ proficiency in German, and their self-perception as heritage speakers and members of the Spanish-speaking culture. The findings reveal that, despite differences in their linguistic biographies and the FLP experienced at home, participants share similar ideologies and identity concepts. These are shaped by a predominantly monolingual view of language, which ultimately hinders the maintenance and transmission of Spanish.