Purpose: To explore change in activity levels post-stroke. Methods: We measured activity levels using the activPAL (TM) in hospital and at 1, 2 and 3 years' post-stroke onset. Results: Of the 74 participants (mean age 76 (SD 11), 39 men), 61 were assessed in hospital: 94% of time was spent in sitting/lying, 4% standing and 2% walking. Activity levels improved over time (complete cases n = 15); time spent sitting/lying decreased (p = 0.001); time spent standing, walking and number of steps increased (p = 0.001, p = 0.028 and p = 0.03, respectively). At year 3, 18% of time was spent in standing and 9% walking. Time spent upright correlated significantly with Barthel (r = 0.69 on admission, r = 0.68 on discharge, both p<0.01) and functional ambulation category scores (r = 0.55 on admission, 0.63 on discharge, both p<0.05); correlations remained significant at all assessment points. Depression (in hospital), left hemisphere infarction (Years 1-2), visual neglect (Year 2), poor mobility and balance (Years 1-3) correlated with poorer activity levels. Conclusion: People with stroke were inactive for the majority of time. Time spent upright improved significantly by 1 year post-stroke; improvements slowed down thereafter. Poor activity levels correlated with physical and psychological measures. Larger studies are indicated to identify predictors of activity levels.