UNLABELLED: The CHIEDZA (Community-based Interventions to improve HIV outcomes in youth: a cluster randomised trial in Zimbabwe) trial evaluated an integrated package of HIV and sexual and reproductive health services for young people aged 16-24 years in Zimbabwe. The family planning component aimed to improve access to information, services, and contraceptives delivered by trained youth-friendly providers within a community-based setting for young women. Responsively adapting the intervention was a part of the intervention design's rationale. We investigated the factors influencing implementation fidelity, quality, and feasibility using provider experiences and perspectives. We conducted provider interviews (N = 42), non-participant (N = 18), and participant observation (N = 30) of intervention activities. The data was analyzed thematically. CHIEDZA providers were receptive to providing the family planning intervention, but contexts outside of the intervention created challenges to the intervention's fidelity. Strategic adaptations were required to ensure service quality within a youth-friendly context. These adaptations strengthened service delivery but also resulted in longer wait times, more frequent visits, and variability of Long-Acting Reversible contraceptives (LARCS) provision which depended on target-driven programming by partner organization. This study was a practical example of how tracking adaptations is vital within process evaluation methods in implementation science. Anticipating that changes will occur is a necessary pre-condition of strong evaluations and tracking adaptations ensures that lessons on feasibility of design, contextual factors, and health system factors are responded to during implementation and can improve quality. Some contextual factors are unpredictable, and implementation should be viewed as a dynamic process where responsive adaptations are necessary, and fidelity is not static. Trial registration ClinicalTrials.gov Identifier: NCT03719521. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s43477-023-00075-6.