Undergraduate research (UR) as a high-impact practice has been increasingly embedded in the curriculum. However, there is a limited understanding of how undergraduates make sense of their research experiences amid an absence of student voice in the literature. This study investigated what students perceived as significant UR experiences through student co-researchers conducting critical incident interviews with fellow students and participating in collaborative analysis. The findings show that students generally perceived their research experiences as positive and associated significant experiences with achievement, ownership, challenges, real-world relevance, collaboration, and to a lesser extent, identification with research. Student co-researchers also provided unique insights such as students paying more attention to the utility value of their UR experiences. This article's main contribution is the discovery of a sense of authenticity in UR from students' perspectives emphasising more real-world relevance while less 'being' and 'becoming', which created challenges to form a researcher identity. The findings also point to both synergies and tensions between achieving authenticity and pursuing utility value, implying the need for enhancing UR through redesigned mentorship in the future.