*Sensing the passage of time is important for countless daily tasks, yet time perception is easily influenced by perception, cognition, and emotion. Mechanistic accounts of subjective time perception have traditionally regarded time perception as part of central cognition. Since proprioception, action execution, and sensorimotor contingencies also affect time perception, perception-action integration theories suggest motor processes are central to the experience of the passage of time. We investigated whether sensory information and motor activity may interactively affect the perception of the passage of time. Two prospective timing tasks involved timing a visual stimulus display conveying optical flow at increasing or decreasing velocity of optical flow, while participants were additionally, independently instructed to imagine themselves moving at increasing or decreasing speed. In the direct estimation task, the duration of the visual display was explicitly judged in seconds while in the motor timing task, participants were asked to keep a constant pace of tapping. The direct estimation task showed imagining accelerating movement resulted in relative overestimation of time, or time dilation, while decelerating movement elicited relative underestimation, or time compression. In the motor timing task, imagined accelerating movement also accelerated tapping speed, replicating the time dilation effect. The experiments show imagined movement affects time perception, suggesting a causal role of simulated motor activity. We argue that imagined movements and optical flow are integrated by temporal unfolding of sensorimotor contingencies. Consequently, as time is relative to motion, so too is perception of subjective time relative to our own subjective motion.* For **predictions**, see: https://aspredicted.org/v7nm5.pdf (November 2020) In the OSF file storage, please see: **- Experiment directory:** * compiled (StarRunner.ebs3) and precompiled (StarRunner.es3) E-Prime 3 experiment runtimes. * stimuli used for temporal estimation. **Data directory:** * StarRunner Real.emrg: behavioural results in E-Prime dataAid format. * Exported.txt: Exported the above for compatibility. * AnalyseInterTapIntervalsInMATLAB: Analysis script for interpolating tapping responses to continuous data and creating the figure below * fig.png: Result of above.