This qualitative study employed a discourse analysis methodology to compare Korean bilingual students in first and third grades by examining different functions and forms of translanguaging in Korean heritage language (HL) classrooms in the U.S. By identifying linguistic functions and forms of each translanguaging occurrence, the study presents that the bilingual students engaged in translanguaging practices in support of their meaning- and sense-making processes. Overall, six translanguaging functions were commonly identified by the first and third graders, but different forms of translanguaging are presented in each grade in support of the functions. The comparison findings from constant comparative analyzes display that the older graders employed translanguaging in more varied forms and for more various purposes than the younger graders because they recognized when to use which language by regulating a higher level of their cognitive thinking skills. As a result, the third graders' translanguaging performance appears to be more strategic and sophisticated than its use by the younger graders. The findings provide pedagogical and methodological implications for educators in bilingual and HL education.