This article reviews the advancements in untethered soft actuators, which are crucial for the functional movements of soft robots. Traditional soft actuators often rely on electrical wires or pneumatic tubes for power supply, limiting their practical applications. Recent breakthroughs in materials and design have led to the development of untethered soft actuators that do not require external power sources, enhancing the mobility and versatility of soft robots. The article discusses four main types of untethered soft actuators: pump-less pneumatic actuators, magnetically-driven actuators, heat-driven actuators, and electrically-driven actuators. Each type is evaluated based on its strengths and limitations, with pump-less pneumatic actuators using phase change materials to generate mechanical force without external pumps, magnetically-driven actuators leveraging magnetic fields for precise and remote control, heat-driven actuators converting thermal energy into mechanical work, and electrically-driven actuators using electrical signals for rapid and precise actuation. The article also highlights the challenges and future perspectives in the field, emphasizing the need for collaboration among researchers, industry, and standardization to advance soft robotics.This article reviews the advancements in untethered soft actuators, which are crucial for the functional movements of soft robots. Traditional soft actuators often rely on electrical wires or pneumatic tubes for power supply, limiting their practical applications. Recent breakthroughs in materials and design have led to the development of untethered soft actuators that do not require external power sources, enhancing the mobility and versatility of soft robots. The article discusses four main types of untethered soft actuators: pump-less pneumatic actuators, magnetically-driven actuators, heat-driven actuators, and electrically-driven actuators. Each type is evaluated based on its strengths and limitations, with pump-less pneumatic actuators using phase change materials to generate mechanical force without external pumps, magnetically-driven actuators leveraging magnetic fields for precise and remote control, heat-driven actuators converting thermal energy into mechanical work, and electrically-driven actuators using electrical signals for rapid and precise actuation. The article also highlights the challenges and future perspectives in the field, emphasizing the need for collaboration among researchers, industry, and standardization to advance soft robotics.