Physical activity (PA) is essential for development of fundamental motor skills (FMS) in children, but it is uncertain which PA intensities are most influential. A limitation to current evidence is the reliance on analytic approaches that cannot handle collinearity. The aim of this study was to determine the PA signature related to FMS in preschoolers, by investigating the association pattern for the whole spectrum of PA intensities using multivariate pattern analysis. We used a sample of N = 1081 Norwegian preschoolers (4.7 yr; 52% boys) who provided valid accelerometer (ActiGraph GT3X+) and FMS data (TGMD-3, modified version). We created 33 PA variables (from 0-100 to =15,000 counts per minute [cpm]), and used partial least squares regression to analyse the associations between PA and FMS, after controlling for potential covariates. PA was positively associated with locomotor- and object control skills (explained variances for vertical axes; R2 = 9.7% and 3.9%, respectively). The strongest associations were found for PA between 5000-8000 cpm. No association pattern was found for PA and balance skills. This study is the first to determine the multivariate PA intensity signature related to FMS. This approach shows that PA within the vigorous range is strongest related to FMS in preschoolers.Abbreviations: FMS: fundamental motor skills; PA: Physical activity; TPA: total physical activity; SED: Sedentary behaviour; LPA: Light physical activity; MPA: Moderate physical activity; VPA: Vigorous physical activity; MVPA: Moderate-to-vigorous physical activity; Min: minutes; cpm: counts per minute; SD: standard deviation; SES: Socioeconomic status; BMI: Body Mass Index.