This paper introduces Thin Soft Robots (TS-Robots), 1.7 mm thick, capable of multimodal locomotion in narrow spaces and across multiple domains (solid, liquid, aerial). These robots utilize a dual-actuation sandwich structure with a tuneable Poisson's ratio tensioning mechanism driven by dielectric elastomers. They demonstrate linear and undulating gaits, high output force (~41 times their weight), and speed (1.16 body length/s and 13.06 body thickness/s). The TS-Robots are shown crawling, climbing, swimming, and collaborating for domain transitions in confined environments.
