SCUBA diving represents a special form of exercise-induced oxidative stress since the increased production of reactive oxygen species (ROS) is a result not only of a demanding physical activity, but also of hyperoxia, which occurs due to breathing oxygen under increased pressure. It is believed that the effectiveness of antioxidant defense enzymes could be dependent on the activity of sirtuins (SIRT), molecules sensitive to the increased production of ROS, which have the ability to increase the expression and activation of antioxidant enzymes. The aim of this study was to examine the effects of scuba diving on oxidative/antioxidative status, as well as SIRT1 and SIRT3 gene expressions in recreational divers after a winter non-dive period. The study included 17 male recreational divers median age (range) 41 (30-52) years. Blood samples were taken before and immediately after diving at a depth of 30 m for 30 min, 3 h and 6 h after diving. The changes of the following parameters were examined: complete blood counts, oxidative damage markers of lipids and proteins in erythrocytes and plasma, by measuring the formation of thiobarbituric reactive substances (TBARS) and protein carbonyl derivatives (PCD), while the activities of antioxidant enzymes; catalase (CAT), total superoxide dismutase (SOD), and isoforms SOD1 and SOD2, as well as CAT, SOD1, SOD2, SIRT1 and SIRT3 gene expression were monitored in peripheral blood mononuclear cells (PBMCs). The increase of leukocyte count and the decrease of erythrocyte count, hemoglobin and hematocrit observed after diving did not show clinical significance. The elevation of CAT, SOD2 and SOD activities observed after diving was not sufficient to prevent the increase in erythrocyte TBARS values. Since we found no difference for plasma TBARS level and also for carbonylated proteins level in either plasma or erythrocytes, peroxidative damage in erythrocytes appears to be the most pronounced response to oxidative stress. Elevation of the antioxidant enzymes activities was not accompanied by the increase of their gene expression. The decrease of SIRT1 gene expression induced by diving, reached its basal level 6 h after the dive, when the increase of SIRT3 gene expression was observed. This study showed that the first dive to 30 m after a non-dive season causes oxidative damage, providing a good basis for further research in the field of recreational diving, which could be useful for forming the diving recommendations. In addition, the observed increase of SIRT3 gene expression contributes to the understanding of the assumed adaptation antioxidant mechanism and the hormesis response to increased ROS production.