The regiment began movement to the combat zone in January 1944 when it sailed from San Diego, California for the enemy held Marshall Islands. The first combat assignment for the regiment was to take part in the seizure of Roi-Namur, twin islands in the Kwajalein Atoll. On 1 February, the regiment assaulted Namur. The 2d and 3d Battalions led the attack. On moving inland the regiment met strong resistance. Second Battalion suffered especially heavy casualties, primarily due to the explosion of an enemy ammunition dump. The island was completely wrested from the Japanese by the following day. The 24th Marines reembarked and sailed for Hawaii two days later. While stationed there, 24th Marines took part in the preparations for the invasion of the Mariana Islands.