A 4D printed liquid crystal elastomer (LCE) biomimetic swimmer is developed using azobenzene-containing photopolymerizable inks. The swimmer is inspired by the ephyra stage of a jellyfish, featuring four lappets arranged in a cross shape. The LCE is fabricated via extrusion printing, allowing precise control over shape and director alignment. When exposed to moderate-intensity UV and green light, the swimmer exhibits rapid, reversible bending of the lappets, resulting in propulsion away from the light source. The photochemical mechanism, rather than photothermal, drives the deformation, as evidenced by the persistence of bending after light is turned off and the recovery via green light. The system eliminates the need for localized lasers or tracking systems, enabling efficient, large-area illumination. The LCE swimmer demonstrates free-swimming motion in water, achieving an average speed of 0.95 mm/s over four cycles. The swimmer's performance is attributed to the photochemical response of azobenzene molecules, which induce significant deformation without heating. The system's ability to operate with moderate-intensity LED light makes it suitable for applications in biomedicine and cell culture, where isothermal processes are desired. The developed LCEs show rapid contraction under UV light, with a 16% reduction in length when submerged in water. The results highlight the potential of LCEs for soft robotics, offering a versatile platform for creating light-fueled free-swimming systems.A 4D printed liquid crystal elastomer (LCE) biomimetic swimmer is developed using azobenzene-containing photopolymerizable inks. The swimmer is inspired by the ephyra stage of a jellyfish, featuring four lappets arranged in a cross shape. The LCE is fabricated via extrusion printing, allowing precise control over shape and director alignment. When exposed to moderate-intensity UV and green light, the swimmer exhibits rapid, reversible bending of the lappets, resulting in propulsion away from the light source. The photochemical mechanism, rather than photothermal, drives the deformation, as evidenced by the persistence of bending after light is turned off and the recovery via green light. The system eliminates the need for localized lasers or tracking systems, enabling efficient, large-area illumination. The LCE swimmer demonstrates free-swimming motion in water, achieving an average speed of 0.95 mm/s over four cycles. The swimmer's performance is attributed to the photochemical response of azobenzene molecules, which induce significant deformation without heating. The system's ability to operate with moderate-intensity LED light makes it suitable for applications in biomedicine and cell culture, where isothermal processes are desired. The developed LCEs show rapid contraction under UV light, with a 16% reduction in length when submerged in water. The results highlight the potential of LCEs for soft robotics, offering a versatile platform for creating light-fueled free-swimming systems.