1965 in the Vietnam War The Viet Cong attack on Pleiku airbase ( aka Camp Holloway Airfield ) occurred on the night of February 6 , 1965 . The attack left eight Americans dead and 128 wounded , and it prompted the United States to launch Operation Flaming Dart against North Vietnam in retaliation . The Vung Ro Bay Incident refers to the discovery of a 100 - ton North Vietnamese naval trawler unloading munitions on a beach in South Vietnam ' s Vung Ro Bay on 16 February 1965 . The incident spurred further U . S . Navy involvement in the Vietnam War . Operation Rolling Thunder , the largest U . S bombing raid against North Vietnam , commences as 100 U . S . fighter - bombers bomb all across targets in North Vietnam . The operation is meant to last eight weeks , but instead lasts three years . March . American units also bomb the Ho Chi Minh Trail , a valuable supply route that ran throughout North and South Vietnam and supported communist forces . The trail is routinely bombed throughout the war with little success as it is consistently rebuilt by North Vietnamese forces . The first American combat troops arrive in Vietnam as 3500 U . S . Marines land at China Beach to defend the American airbase at Da Nang . They join the already 23 , 000 American advisors and this starts principal U . S . involvement in the Vietnam War . Viet Cong troops storm into the U . S . Embassy in Saigon and bomb the area , wounding several Americans . President Johnson authorizes sending two more U . S . Marine battalions and 20 , 000 logistics personnel to Vietnam . May . Australian Defence Force are first deployed to Bien Hoa , north - east of Saigon , South Vietnam . The first U . S . Army troops from the 173rd Airborne Brigade arrive in Vietnam . The Battle of Song Be was a major action between the National Front for the Liberation of South Vietnam ( Viet Cong ) and Army of the Republic of Vietnam ( ARVN ) in May 1965 . The Battle of Ba Gia or Bãi Xoan was a battle of the Vietnam War , that began after an ARVN battalion was ambushed by Viet Cong ( VC ) forces on May 28 , 1965 . The battle highlighted the vulnerability of the ARVN as a military force against the flexible VC . The Battle of Đồng Xoài was waged by the National Liberation Front , otherwise known as the Viet Cong , during the Communist winter - spring offensive of 1965 . It was the largest battle during that stage of the Vietnam War . July . Communist China begins to send troops to help defend the northern reaches of North Vietnam . The USSR also starts to send men to Vietnam . Members of the New Zealand armed forces are deployed to South Vietnam . Operation Starlite was the first offensive military action conducted by a purely U . S . military unit during the Vietnam War . The operation was launched based on intelligence provided by Major General Nguyen Chanh Thi , the commander of the South Vietnam ese forces in northern I Corps area . Lieutenant General Lewis W . Walt devised a plan to launch a pre - emptive strike against the Viet Cong regiment to nullify the threat on the Chu Lai base . The Siege of Plei Me was a battle during the Vietnam War , which led up to the Battle of Ia Drang . Operation Hump was a search and destroy operation by the 173rd Airborne Brigade , in an area about 17 . 5 miles north of Bien Hoa . The 1st Battalion , Royal Australian Regiment , deployed south of the Dong Nai River while the 1st Battalion , 503rd Infantry , conducted a helicopter assault on an LZ northwest of the Dong Nai and Song Be River s . The Battle of Gang Toi was fought on 8 November 1965 between Australian troops and the Viet Cong , during the Vietnam War . The battle was one of the first engagements between the two forces during the war and occurred when the 1st Battalion , Royal Australian Regiment ( 1RAR ) struck a Viet Cong bunker system in the Gang Toi Hills , in northern Bien Hoa Province . The Battle of Ia Drang was one of the first major battles between the United States Army and the People ' s Army of Vietnam ( PAVN ) referred to by US fighting units as the North Vietnamese Army ( NVA ) during the Vietnam War . Operation Game Warden Task force 116 , was an operation to deny Viet Cong access to the resources in the Mekong Delta which was conceived of in December 1965 .