© 2020 Informa UK Limited, trading as Taylor & Francis Group. Epidemiological data suggests that the genesis of cardiovascular disease occurs during childhood. Sedentary time (ST) is a main driver of high blood pressure (BP) in adolescents and adults. However, associations between ST and cardiovascular health in young children are uncertain. Prospective associations between ST and BP were assessed among 172 toddlers (88 boys), aged 19.5 ± 3.9 months at baseline, recruited from the GET‐UP! Study, Australia and followed over a 12-month period. BP was measured with a digital monitor and z-scores were computed by age and sex for systolic and diastolic BP. Total ST was measured over 7 days using Actigraph accelerometers and expressed over a 24-h period. Multilevel linear regression models were used to assess regression coefficients and standard errors, predicting BP at follow-up from ST at baseline. Analyses controlled for socio-economic status, height, age, gender, group (intervention or control) and zWC at baseline. Adjusted analyses showed that total ST did not predict systolic or diastolic BP (β = 0.0009, p = 0.368 and β = 0.002, p = 0.05, respectively). Most likely, longer follow-up periods might be needed to confirm or rule out our results, as the effects of cumulative ST over time on BP values are prone to manifest later in life and track into adolescence and adulthood.