Hence, the exploration and exploitation of marine resources are crucial to human development. However, due to the deep sea's low temperature, high pressure, and complex fluid environment, it is difficult for human beings to easily investigate and work there. As a result, only 5% of Earth's oceans have been explored. Fortunately, thanks to recent rapid developments in science and technology, underwater robotics has seen explosive growth, giving humans a powerful tool to explore the world's oceans, which are expected to play a key role in the underwater rescue, submarine inspection, and hydrological monitoring. [2,3] Recently, with the fast development of bionic technology, [4][5][6][7][8][9] advanced underwater experimental platforms, [10][11][12][13][14] and computational science, [15][16][17][18][19][20] researchers have a deeper understanding of the swimming mechanism of aquatic organisms, which has promoted the explosive growth of underwater robots. [21][22][23][24][25] For example, Zhang et al. [26] developed a gliding robotic fish for long-duration monitoring of underwater environments by combining underwater gliders and robotic fish. Yu et al. [27] developed a biomimetic robot dolphin that, by controlling the pitch angle and swimming speed, could successfully jump out of the water. Lauder and coworkers [28] designed a fast-swimming robot tuna that, through the high-frequency oscillation of the caudal fin, could achieve a maximum tail beat frequency of 15 Hz, which corresponds to a swimming speed of 4.0 body lengths per second (BL S −1 ). However, most underwater robots are driven by motors that are bulky in structure and lack essential safety. In the execution of underwater missions, it is not only easy to cause harm to marine organisms, but it is also difficult to complete required tasks due to poor overall flexibility. Moreover, a rigid robot body driven by a motor suffers from high noise output and a low battery energy conversion rate, meaning that the robot is unable to realize long-term and long-distance tasks. A high noise output can also expose the position of the underwater robot. Overall, the shortcomings of rigid robotic fish significantly restrict application at sea. It is an urgent need to develop high-performance underwater swimming robots with new propulsion methods and bionic structures. Benefiting from the rapid development of materials science and intelligent manufacturing, soft underwater swimming robots have become a hot topic of research. Compared with With the increasing requirements of underwater missions and the rapid development of soft robotics technologies, soft underwater swimming robots have become a hot topic of research due to their low noise, high flexibility, and high environmental adaptability. In the past 10 years, research into soft underwater robots based on artificial muscle actuation has made considerable progress. Herein, a comprehensive survey on recent advances in soft underwater swimming robots based on different actuation methods is reviewed systematically, includi...