The prevalence of seasonal variation in vitamin D status was examined in 20 FA Premier League soccer players residing at a latitude of 53°N. Serum 25-hydroxyvitamin D (25(OH)D) levels decreased (P < 0.001) between August (104.4 ± 21.1 nmol·L(-1), range 68-151) and December (51.0 ± 19.0 nmol·L(-1), range 22-86), such that levels for 65% of the sample were insufficient (<50 nmol·L(-1)) in winter. Strategies to augment vitamin D(3) availability may therefore be advantageous for UK soccer players so as to maintain muscle function.