Final North Vietnamese offensive Further information on the final North Vietnamese offensive: Ho Chi Minh Campaign With the north half of the country under their control, the Politburo ordered Dũng to launch the final offensive against Saigon. The operational plan for the Ho Chi Minh Campaign called for Saigon's capture before 1 May. Hanoi wished to avoid the coming monsoon and prevent redeployment of ARVN forces defending the capital. PAVN forces, their morale boosted by their recent victories, rolled on, taking Nha Trang, Cam Ranh and Da Lat.[25]: 702–704

On 7 April, three PAVN divisions attacked Xuân Lộc, 40 miles (64 km) northeast of Saigon. For two weeks, fighting raged as the ARVN defenders made a last stand to try to block PAVN advance. On 21 April, however, the exhausted garrison was ordered to withdraw towards Saigon.[25]: 704–707  An embittered and tearful Thiệu resigned, declaring that the US had betrayed South Vietnam. In a scathing attack, he suggested Kissinger had tricked him into signing the Paris peace agreement, promising military aid that failed to materialize. Having transferred power to Trần Văn Hương on 21 April, he left for Taiwan.[25]: 714  After having appealed unsuccessfully to Congress for $722 million in emergency aid for South Vietnam, Ford gave a televised speech on 23 April, declaring an end to the War and US aid.[212][213]

By the end of April, the ARVN had collapsed except in the Mekong Delta. Refugees streamed southward, ahead of the main PAVN onslaught. By 27 April, 100,000 PAVN troops encircled Saigon. The city was defended by about 30,000 ARVN troops. To hasten a collapse and foment panic, the PAVN shelled Tan Son Nhut Airport and forced its closure. With the runways closed, large numbers of civilians had no way out.[25]: 716

Fall of Saigon Main articles: Fall of Saigon and Operation Frequent Wind Chaos and panic broke out as South Vietnamese officials and civilians scrambled to leave. Martial law was declared. American helicopters began evacuating South Vietnamese, US and foreign nationals from Tan Son Nhut and the U.S. embassy compound. Operation Frequent Wind had been delayed until the last possible moment, because of Ambassador Graham Martin's belief Saigon could be held and a political settlement reached. Frequent Wind was the largest helicopter evacuation in history. It began on 29 April, in an atmosphere of desperation, as hysterical crowds of Vietnamese vied for limited space. Frequent Wind continued around the clock, as PAVN tanks breached defenses near Saigon. In the early morning of 30 April, the last US Marines evacuated the embassy by helicopter, as civilians swamped the perimeter and poured into the grounds.[25]: 718–720

On 30 April 1975, PAVN troops entered Saigon and overcame all resistance, capturing key buildings and installations.[214] Tanks from the 2nd Corps crashed through the gates of the Independence Palace and the VC flag was raised above it.[215] President Dương Văn Minh, who had succeeded Huong two days earlier, surrendered to Lieutenant colonel Bùi Văn Tùng, political commissar of the 203rd Tank Brigade.[216][217][218]: 95–96  Minh was then escorted to Radio Saigon to announce the surrender declaration.[219]: 85  The statement was on air at 2:30 pm.[218]