In this article, the drag characteristics of an underwater vehicle propelled by a synthetic jet (SJ) is numerically studied. The underwater vehicle studied is REMUS Autonomous underwater vehicle (AUV). The cruising speed studied is up to 10 knots. The actuation parameters of the SJ actuator are the same under different cruising speeds. When the SJ actuator works, the drag of the vehicle changes periodically. The SJ-induced additional pressure drag increases with increasing cruising speed. The additional friction force is negligible. The thrust of the actuator decreases with increasing cruising speed. The thrust outputted by the SJ actuator when used for underwater vehicle propulsion is smaller than the thrust of an isolated actuator. The mathematical model of the additional drag, the model of the thrust, and the velocity distribution is given to assist the analysis in this article.