It has been proposed that regular cold swimming is associated with health benefits. However, the effect of cold adaptation on particular cardiovascular risk factors, within a single swimming season, remains unknown. Our aim was to evaluate the impact of cold water swimming on the seasonal changes in lipid profile and on apolipoprotein and homocysteine concentration in 34 cold water swimmers (CWS) aged 48 - 68 years. Blood samples were collected at the beginning (October), the middle (January), and the end (April) of the swimming season. Body mass (BM), total cholesterol (TC), high-density lipoprotein (HDL), low-density lipoprotein (LDL), triglycerides (TG), ApoB/ApoA-I ratio, and homocysteine concentrations were evaluated. In October, female CWS showed lower BM (P = 0.01), TG concentrations (P = 0.03), and ApoB/ApoA-I ratios (P = 0.008), and higher HDL (P = 0.01) than in men. Similar trends in BM (P = 0.002), HDL (P = 0.0006), and ApoB/ApoA-I ratio (P = 0.01) were seen in January, and for BM (P = 0.002), TG (P = 0.005), HDL (P = 0.003), and ApoB/ApoA-I (P = 0.01) in April. A decrease in TG concentration between January and April (P = 0.05), lower homocysteine concentration between October and January (P = 0.01), and between October and April (P = 0.001) were documented in CWS. A strong drop in homocysteine concentration was observed in female versus male CWS (P = 0.001 versus P = 0.032), particularly between October and April in women (P = 0.001) and October and January in men (P = 0.05). The ApoB/ApoA-I ratio in female CWS decreased over the season (P = 0.02), particularly between October and January (P = 0.05), and a trend toward the TG concentration to reduce over the swimming season was also observed in female CWS. No beneficial changes were noticed in the control group over the season. Our results suggest that the favorable effect of cold swimming on the cardiovascular risk factors may be gender-dependent; further studies are thus needed to draw a precise conclusion.