The presenter will report on a qualitative investigation of Japanese college students' learning experience in teletandem. During the COVID-19 pandemic, a group of Japanese female college students had joined a series of language learning sessions with American college students online since October 2020. Drawing on the analysis of pre-/post-questionnaires, student reflections, and interviews, the researcher will discuss the impact of tandem learning in the online environment, particularly on the students’ self-concepts in L2 learning.