We present a quantitative study of responses to voluntary and anonymous surveys of undergraduate geology students enrolled at an English-medium, research university in South Africa. This research captured student interest in geology, their perceived level of understanding of key geological concepts, and the extent to which in-class and in-field experiences impacts both. The first survey was prior to undergraduate field trips (May 2021) and was followed by the post-field second survey (November 2021). The surveys included Likert-type responses, multiple choice responses, and open-ended qualitative comments from the students. Of the total responses (n = 147), 83% knew "a little" about geology before starting their degree, and most (63%) chose to study geology because of an inherent interest in the earth. Up to 40% of students perceived that practicals helped them to better understand theoretical content, including key geological concepts. Of the five key geological concepts examined, the students felt that plate tectonics, age relationships, and uniformitarianism were "easy" to grasp, but deep time and 3-D perception could only be understood once in their fourth year. Field experiences were perceived to improve students' conceptual understanding of all five concepts, and this study suggests that field work enhances student interest in geology. However, further interest can be promoted using more in-field exercises and hands-on practicals dealing with real-world geological situations. Overall, the results suggest that in-field and practical abilities in geology remain critical, as they stimulate understanding of key concepts and, if pitched correctly, generate and sustain the interest of geoscience students.