["European Journal of Education, Volume 61, Issue 2, June 2026. ", "\nABSTRACT\nThis study explores how international and interdisciplinary research collaboration is experienced and sustained in practice, with particular attention to the roles of early‐career researchers (ECRs). Drawing on a collaborative autoethnographic approach, we analyse four collaboratively constructed narrative vignettes from a three‐year UK–China research project. The vignettes capture researchers' lived experiences of working across epistemic, cultural and institutional boundaries. The findings show that collaboration is sustained not primarily through formal coordination or technical alignment but through ongoing negotiation of epistemic boundaries, power asymmetries and care practices in collaborative work. ECRs frequently encounter epistemic boundaries as sites of uncertainty, legitimacy negotiation, and vulnerability, shaped by career stage, institutional location and governance contexts. Meanwhile, they occupy intermediary roles as linguistic, disciplinary and cultural mediators, making them indispensable while exposing them to disproportionate epistemic and relational labour. The analysis further shows that care practices, such as attentiveness, reflexivity, emotional support and coordination across differences, are central to sustaining collaboration. When care labour is privately absorbed by ECRs, collaboration risks exhaustion; when recognised and embedded in collective and leadership practices, it supports sustainable collaboration. Methodologically, the study demonstrates the value of CAE for revealing the micro‐dynamics of collaborative research.\n"]