In sociolinguistic interviews for a research project on cross-cultural marriage, 27 out of 73 second language (L2) users of English and German were found to claim that they had achieved high-level proficiency in their L2 and that they were passing for native speakers in some contexts. Based on these insiders' accounts, the article provides a description of passing for a native speaker as a (frequently overlooked) form of L2 ability. The introduction discusses ethnographic research into success in second language learning (SLL) and explains why other approaches tend to identify a significantly lower incidence of high-level achievement. Quantitative analysis of the data suggests that the age of first exposure to the target language is far less crucial to success than has so far been assumed. The L2 users themselves distinguish between age of first exposure and age when they 'really' started to learn their L2, thereby pointing to the role of motivation and agency in successful SLL. Qualitative analysis of the L2 users' accounts indicates that, for them, passing practices are quite different from widely held assumptions about passing. Passing is described as a temporary, context-, audience- and medium-specific performance. The article ends with a discussion of the evaluation of passing and its role in (perceived) success in SLL.