After two more uneventful patrol and training missions between Japan and the Marianas Islands, "Ryūhō" was sent to the Japanese anchorage at Tawi Tawi in May 1944 to join the Combined Fleet. From there, she sailed with the Combined Fleet to participate in the First Battle of the Philippine Sea. On 19 June, she launched an air strike against Task Force 58, but scored no hits; nearly all of "Ryūhō's" aircraft were shot down by the swarms of American F6F Hellcat fighters and the anti-aircraft guns of the American fleet. On 20 June, as part of "Force B" (with the carriers "Hiyō", , the battleship , the cruiser and eight destroyers), "Ryūhō" was attacked by four Grumman TBF Avenger torpedo bombers from the aircraft carrier . She suffered only slight damage from near misses.