This paper draws on identity narratives that were collected annually over a four-year period from two heritage language learners of Japanese at a U.K. university. This paper observes how 'fixity' (discreteness, static and fixed identities) and 'fluidity' (hybridity; creative and flexible identities) co-exist with each other in learners' conceptualization of themselves and their cultural affiliations. The findings of this study indicate a high degree of complexity and flux within the identities of these learners, enabling them to shift between fixed and fluid conceptualizations of themselves. One student deliberates the association between her nationality and personal identity, while also expressing fixed views on what it means to be Japanese on other occasions. The other student uses 'fixed' categories such as 'foreigner' in a fluid way to construct the self-image(s) that suit his varied purposes. The article concludes with research and pedagogical implications for conducting research on the identity of heritage language learners.