While existing literature highlights the need to integrate translanguaging into assessments, its classroom application remains understudied. Adopting a participatory research approach, this study illustrates (1) how translanguaging was incorporated into formative assessments in a Chinese immersion context and (2) the perspectives of both the teacher and students regarding the assessments. The teacher and I co-designed formative assessments, integrating them into the translanguaging instruction design cycle (García, O., S. I. Johnson, and K. Seltzer. 2017. "The Translanguaging Classroom: Leveraging Student Bilingualism for Learning." Carlson: Multilingual Matters) for an academic unit. The data included notes from co-planning sessions, classroom observations, artifacts, and transcripts of interviews with the teacher and students. The results demonstrate that the teacher and students mobilized various communicative resources to assess and demonstrate knowledge. The teacher also skillfully integrated the gradual release model into the implementation of the assessments to scaffold students' progression. These formative assessments offered insights into student learning and allowed them to leverage multilingualism in a co-learning environment. The students reported positive experiences with the assessments. Not only did they apply the key concepts learned within the unit but also developed confidence, expanded proficiency in Chinese, and acquired an appreciation for other languages. Based on these findings, practical recommendations for incorporating translanguaging into formative assessments are discussed.