Commander, Undersea Surveillance web page has 1 April 1955 as commissioning date. Photographs of the commissioning on the IUSS/Caesar Alumni Association site have the actual ceremony date as 1 May 1955. A note on the photo Four of the "Original Five" WRENs at Shelburne 1955 (referenced below) that the fifth WREN, Lois, "was on watch" shows that the commissioning ceremony took place after operations began.