Cavitation erosion tests of high tensile stainless steels for the Techno-Superliner (TSL-F) hulls were carried out. The TSL-F is a new generation, high-speed, hybrid hydrofoil lift/buoyancy type vessel. The hull structure consists of an upper hull, lower hull, hydrofoils and struts which connect the upper hull to the lower hull and hydrofoils. A 13 Cr-5 Ni martensite, a 24 Cr-13 Ni austenite which is produced by a new thermo-mechanical controlled rolling process (TMCP) and a 22 Cr-5 Ni dualphase stainless steel were examined, whose tensile strength ranged from 1078 MPa to 710 MPa, by three methods ; i. e., a vibratory method, a high speed fluid channel method and the test using a 1/6 scale sea going test ship. It became clear that these materials have better anti-cavitation erosion properties compared to other conventionally used structural materials such as a mild/high-tensile steel and have the same properties as 15-5 PH (precipitation hardening) stainless steel which is well known as a high tensile stainless steel and that the vibratory method and the high speed fluid channel method gave the same characteris-tics qualitatively. Finally, a rough estimation of the total life cavitation erosion of an actual TSL-F was done by using these three test results.