Self-efficacy has been linked to academic performance, motivation, and progression within engineering degree programs. Such associations are context specific, and an understanding of sources of self-efficacy is paramount to guiding policy and practice enhancements. We sought to understand the self-efficacy beliefs held by 1st year engineering students on a common entry program in Ireland prior to their choosing of a field of engineering to pursue for the remainder of their undergraduate studies. A mixed-methods survey design was adopted. Self-efficacy was quantitatively measured at the beginning and end of the participants second semester using the scale developed by Mamaril et al. (Mamaril, N. A., E. L. Usher, C. R. Li, D. R. Economy, and M. S. Kennedy. 2016. "Measuring Undergraduate Students' Engineering Self-Efficacy: A Validation Study." "Journal of Engineering Education" 105 (2): 366-395. https://doi-org.bibliotheek.ehb.be/10.1002/jee.20121.). Data was gathered pertaining to general and three distinct domains of engineering self-efficacy. In the post-survey, open questions were added to capture qualitative insight regarding participants' views on the sources of their beliefs. A partial replication of the results of Mamaril et al. (Mamaril, N. A., E. L. Usher, C. R. Li, D. R. Economy, and M. S. Kennedy. 2016. "Measuring Undergraduate Students' Engineering Self-Efficacy: A Validation Study." "Journal of Engineering Education" 105 (2): 366-395. https://doi-org.bibliotheek.ehb.be/10.1002/jee.20121.) was observed suggesting possible contextual impacts on specific dimensions of student self-efficacy. Female students began the semester with significantly lower tinkering skills self-efficacy to male students, with female students general engineering self-efficacy increasing statistically more over the semester within a CDIO module. Qualitative findings indicate context-specific gendered experiences perceived as impacting student self-efficacy.