"Accessibility" features promote inclusive education but do not guarantee it. Communication accessibility, such as sign language interpretation or note-taking, may facilitate the academic inclusion of deaf students in general classrooms but does not necessarily enable their full social inclusion. Whereas in general classrooms deaf students are often the only deaf person present, in co-enrollment programs a "critical mass" of deaf students is educated alongside their hearing peers. These co-enrollment programs may employ a wide range of communication modalities; however, sign bilingualism has the greatest potential to create a socially inclusive environment, because deaf and hearing children can communicate directly without mediation. In this article, I explore the potential of sign bilingual co-enrollment programs as pathways to belonging, or ibasho, in Japanese education. The analysis is based on existing research on co-enrollment practices across the globe, an in-depth interview and ongoing correspondence with one of the founding members of the first co-enrollment program in the world, as well as my long-term fieldwork with deaf communities in Japan. Based on these findings, I argue that sign bilingual co-enrollment environments go beyond cosmetic accessibility to true inclusivity, creating opportunities for peer interactions, meaningful communication, and belonging.