Efficient low-speed Autonomous Underwater Vehicles (AUV) could adopt a propulsion mechanism with a biomimetic approach of caudal fin propulsion. The developments of the biomimetic AUV have very little attention to the systematic enhancement scheme of the fin performance. Therefore, many unclear relations of the parameters in thrust generation and efficiency of the various types of biomimetic fins. The present study proposes a systematic enhancement scheme of the static and dynamic performances of the biomimetic fins in a low-speed regime. This scheme involves rigid, cupping, and flexible single-joint fins of the acceleration-reaction fin mechanism and a high aspect ratio lunate shape two-joint fin of the lift-based fin mechanism. Average net-force and Thrust-to-Power Ratio evaluated the static performance, while the estimated cruising speed characterized the dynamic performance. The present study shows that the flexible single-joint fin improved the maximum values of the rigid fin performance by three times in average net-force, five times in thrust-to-power ratio, and two and a half times in estimated cruising speed. The two-joint fin enhanced the static and dynamic performances of the flexible fin by three times in average net-force, four times in thrust-to-power ratio, and one and a half times in estimated cruising speed. The present study suggests that flexibility has a role as a thrust vectoring factor. Furthermore, the lift-based mechanism in the two-joint fin provides effective and efficient thrust generation. In the present study, the two-joint fin was the effective and efficient fin propulsion mechanism in a low-speed regime.