Physiotherapy is one of the most burdensome aspects of cystic fibrosis (CF) care. Healthcare requirements for older children with CF are reported to impact parental quality of life and physiotherapy adherence. How parents of infants experience performing chest physiotherapy as a part of CF care is unknown. This study aimed to explore the experience of performing chest physiotherapy for parents of infants with CF. In this study, 13 parents of infants (aged 1–2 years) with CF participated in one in-depth semi-structured interview and completed a daily diary for five days. Principles of hermeneutic phenomenology guided interpretation of interview transcripts, diary entries, and field notes. For these parents, being responsible for performing chest physiotherapy was an ever-present experience of pressure, doubt, and guilt. Managing chest physiotherapy resulted in sacrifices that were perceived by parents as an expected and necessary part of meeting the healthcare needs of their child. Despite perceived sacrifices, performing chest physiotherapy was also experienced by parents as an opportunity to positively impact the health of their child. Awareness of parental perceptions and experiences of chest physiotherapy in CF may enhance the personalization of physiotherapy and minimize burden.