Baseline mystery client data were collected in 2022 from public-sector health facilities in Kisumu County, western Kenya, as part of the SAFI-FP social accountability trial. Trained mystery clients visited study facilities using standardized profiles and protocols to assess the availability, accessibility, and quality of family planning services from the perspective of a client seeking care. After each visit, mystery clients completed a structured questionnaire documenting facility access, provider availability, waiting time, counseling content, method availability, fees or informal payments, respectful treatment, provider-imposed restrictions, and whether the client was offered or denied her preferred contraceptive method. Data were collected on password-protected and encrypted tablets using the SurveyCTO platform. The public-use dataset contains de-identified visit-level records.