Crowberries (Empetrum nigrum L.) exhibit strong antioxidant activity due to their abundant anthocyanin content. This study investigated regional and seasonal variations in anthocyanin content and antioxidant activity in crowberries collected from five distinct regions in Sweden. Quantitative analyses using 1H-NMR and high-performance liquid chromatography revealed anthocyanin concentrations ranging from 3.2 to 8.9 μmol/g fresh weight, with higher levels observed in fruits harvested earlier in the season. Antioxidant activities, determined by ORAC (62.6–128.7 μmol TE/g), ABTS, FRAP, and DPPH assays, showed both assay-dependent and sample-dependent variations, with no consistent trends across regions or harvest periods. Principal component analysis of the 1H-NMR data effectively differentiated crowberry samples according to harvest time and geographical origin, linking earlier harvests to increased levels of cyanidin and delphinidin glycosides.