On 13 June 1944, Admiral Soemu Toyoda activated "Operation A-GO" for the defense of the Mariana Islands. "Tone" was assigned to Force "C" of Vice Admiral Jisaburo Ozawa's Mobile Fleet, which proceeded through the Visayan Sea to the Philippine Sea headed towards Saipan. On 20 June, after the battleships , and carrier were attacked by aircraft from the carriers , and and the bulk of the Japanese air cover was destroyed in the "Great Marianas Turkey Shoot", "Tone" retired with the Mobile Fleet to Okinawa, and from there to Kure. While at Kure from 26 June to 8 July 1944, "Tone" gained additional Type 96 25-mm AA, bringing its total to 57. Two new Type 22 surface-search radars and a Type 13 air-search radar were also fitted. After ferrying army troops to Okinawa, "Tone" was reassigned back to Singapore in July.