In this study, self-sealing polyethylene (PE) was successfully achieved via incorporating super-absorbent polymer (SAP). Attributed to the high thermal stability, the SAP particles can survive through the harsh processing conditions during thermal extrusion and hot pressing. PE specimens with different concentrations of SAP particles of different sizes show good sealability with fast response to water penetration through pin-hole and crack defects. It was observed that a higher concentration of smaller SAP particles enables better sealing performance under normal pressure. Additionally, repeated sealing can be achieved with full sealability due to the left SAP residue from the last cycle in the defects.