Traditional geology field camps are immersive, long-duration (often 4–6 weeks), in-person capstone courses emphasizing hands-on data collection in natural settings, direct outcrop observation, and geologic mapping. These courses are widely valued for authentic student engagement with Earth systems and synthesis of core geoscience skills, yet systematic evidence of their impact on both technical skills and affective outcomes remains limited. We report on a four-year, mixed-methods study (2021–2024) of a month-long, mobile undergraduate field camp that used the Learning Outcomes for Capstone Field Experiences (LOCFEs) as a community-derived assessment framework. Pre- and post-field camp surveys (65 paired respondents) and post-field camp reflections (n = 68) revealed very large perceived gains in technical competencies (mean normalized change 45%, Cohen's d = 1.81), as well as substantial affective growth in science identity (38%, d = 0.80), grit (34%, d = 0.95), and other personal outcomes, despite some ceiling effects. Survey control items (related to biogeochemical cycling, seismology, and GIS—topics not covered in the curriculum) confirmed that gains were specific to the field camp experience. Qualitative reflections highlighted the value of embodied, sustained fieldwork and supportive peer and instructor communities for student growth. We release a tested LOCFE–aligned instrument for broader use in geoscience education research and practice. These findings reinforce the enduring pedagogical value of traditional field camps and demonstrate measurable affective growth, pointing to opportunities for future program improvement and inclusivity. Attendees will gain insights into using LOCFE–aligned frameworks to assess field experiences and the implications for supporting both technical and affective student development.