The present study was performed to investigate the energetics of surface events (SE) in finswimming by analyzing the concepts of critical velocity (Vcri) and anaerobic swimming capacity (ASC). Ten finswimmers (five males and five females, aged 24±6 years), who were members of the Japanese national team, performed maximal effort swimming over five test distances (100 m, 200 m, 400 m, 800 m, and 1500 m). The distance-time relationship for the 200-m, 400-m, and 800-m distances showed a linear relationship (r²>0.99) in all subjects. Therefore, Vcri was calculated for these three distances, and ASC was defined as the y-intercept of the regression line between distance and time. A significant correlation was found between the mean velocity (V-) over each distance and Vcri (r=0.76-99). ASC was significantly correlated with V-100 m, V-200 m, and V-400 m (r=0.69-81). Furthermore, ASC was significantly correlated with the residual error of V-800 m (r=0.90) or V-1500 m (r=0.71) calculated by regression analysis of the relationship between Vcri and V-800 m or V-1500 m. The results of this study suggest that aerobic performance contributes to finswimming performance over distances ranging from 100 m to 1500 m. Although anaerobic performance also contributes to performance over distances of less than 400 m, it makes very little contribution over distances of 800 m and 1500 m.