Understanding incarcerated adult (IA) students’ fears upon entering a CS1 course and how their confidence changes throughout the course can help us understand how well IA students’ fears are being addressed, and help future instructors of CS1 in prison address them better. Building on recent work on non-CS majors’ fears and confidence in introductory CS, we surveyed 45 IA students across two offerings of a CS1 course in prison on their fears going into the course, and confidence in their ability to succeed. We present a phenomenographic analysis of fears amongst IA students in CS1, and analyze relationships between these fears and change in confidence. In addition, we compare the fears expressed by IA students to those of non-CS majors from prior work. Findings include many IA students reporting no fears, but an overall decrease in confidence across both offerings of the course which was mostly accounted for by students who did express initial fears. We found 9 fears overlapping with those found in a prior study outside of the prison context (e.g., getting a bad grade), and 7 fears only identified in our study (e.g., interference from circumstances beyond my control).