The PACE Definitive Ephemeris Data collection provides high-precision, post-processed spacecraft ephemeris records for NASA’s Plankton, Aerosol, Cloud, ocean Ecosystem (PACE) mission, describing the satellite’s reconstructed orbital position and velocity over time. These definitive ephemerides represent the most accurate estimate of the PACE spacecraft trajectory based on ground-processed tracking and navigation data and are used as ancillary information to support precise geolocation, calibration, and higher-level processing of PACE science observations from instruments such as OCI, HARP2, and SPEXone. The dataset has global coverage and is intended for use in mission operations, science data processing, and reprocessing activities that require accurate knowledge of the spacecraft’s orbit.