This data package provides post-processed data used in the manuscript “Temporal variability in biomechanics and within-plant heterogeneity regulate flow-seagrass interactions”authored by Davide Vettori and Timothy I. Marjoribanks. The data package contains data obtained from direct measurement of maximum quantum yield of fluorescence, morphological characteristics and mechanical properties of the seagrass species Zostera marina collected in the Rodsand lagoon (DK). Further, data of seagrass drag force, biomass height, and deflected height computed by using a numerical model of flow-seagrass interactions are provided. The numerical model was parameterized using data from direct measurements.