The devastating defeats suffered by the ARVN prompted South Vietnam's National Assembly to question President Nguyễn Văn Thiệu's handling of the war, thereby placing him under tremendous pressure to resign.

Once Xuân Lộc fell, the PAVN battled with the last remaining elements of III Corps Armored Task Force, remnants of the 18th Infantry Division and depleted Marine, Airborne and Ranger Battalions in a fighting retreat that lasted nine days, until they reached Saigon and PAVN armored columns crashed through the gates of South Vietnam's Presidential Palace on 30 April 1975, effectively ending the war.

Thiệu, in response to the Senate's recommendations, immediately approved Tran Thien Kiem's resignation and swore in Nguyễn Bá Cẩn as the new Prime Minister.

[7]: 63 During a meeting with the Chief of Staff of the United States Army, General Frederick C. Weyand on 3 April, Thiệu outlined his strategy to defend South Vietnam, vowing to hold what was left of his country.

[7]: 59  Eventually, the meeting became more intense when Thiệu produced a letter written by former U.S. President Richard Nixon, which promised military retaliation against North Vietnam if they violated the terms of the Paris Peace Accords.

Unlike in the previous three years, South Vietnamese defences around Tây Ninh and Bình Dương were significantly weakened due to a lack of manpower and resources.

Even though Tây Ninh and Bình Dương did not play a significant role in the defensive posture of South Vietnam, large ARVN units made their way into those areas as a result of the early defeats in 1975.

To stop ARVN units from gathering in Tây Ninh and Bình Dương, and thereby regrouping for further resistance, the North Vietnamese decided to capture those regions.

[3]: 219 The PAVN 4th Army Corps Command selected Dầu Tiếng–Chon Thanh as the first target for their operation, as it was the weakest point in the South Vietnamese defensive line in the north-west area.

[9]: 3 On the afternoon of 11 March, ARVN General Lê Nguyên Khang ordered the 345th Armored Squadron to move out from Bau Don to relieve the military zone of Dầu Tiếng, but they were defeated by the PAVN 16th Infantry Regiment at Suoi Ong Hung, and forced to retreat to their base.

After three hours of fighting, the PAVN 9th Infantry Division also captured ARVN positions at Vuon Chuoi, Nga ba Sac, Cau Tau and Ben Cui.

The ARVN 3rd Brigade had planned to retake Dầu Tiếng using elements of the 5th Division, but Thiệu ordered them to pull back and defend Truong Mit, Bau Don and Tây Ninh instead.

[2]: 104–5 The PAVN began their Long Khánh-Bình Tuy campaign with strong attacks against ARVN positions on the two principal lines of communication in the region, Highways 1 and 20, striking outposts, towns, bridges and culverts north and east of Xuân Lộc.

The PAVN assault was repulsed with heavy losses on both sides, and another RF company, sent to reinforce, ran into strong resistance on Highway 1 west of Ong Don.

North from Xuân Lộc, on Route 20, hamlets along the road were occupied to varying degrees by PAVN soldiers, and the RF outpost far to the northeast near the Lam Dong boundary was overrun.

III Corps commander Lieutenant General Nguyễn Văn Toàn responded to the burgeoning threat on his eastern flank first by sending the 5th Armored Cavalry Squadron and then one battalion of the 48th Regiment from Tây Ninh to Long Khánh.

The 3rd Battalion made contact with a PAVN company west of the Vàm Cỏ Đông River on 17 March, killed 36, and captured a number of weapons.

[10]: 169 After capturing all key objectives surrounding Xuân Lộc in Long Khánh Province, the PAVN 4th Army Corps spent four days preparing for the final push against the ARVN 18th Division.

PAVN Major General Hoàng Cầm personally took control of the operation; he decided to launch a full-frontal assault on Xuân Lộc using his infantry, tank and artillery units from the north and northwest.

The regiment moved to the Xuân Lộc area but sent its 2nd Battalion to Hàm Tân District on the coast of Bình Tuy Province to secure the city and port.

North of the town, the PAVN 341st Infantry Division captured the ARVN communications center and the local police station after more than an hour of heavy fighting.

Subsequently, the ARVN 1st Airborne Brigade arrived at the Bao Dinh rubber plantation, while two Marine battalions defended the eastern corridor leading to Bien Hoa.

As the reinforcements were making their way onto the battlefield, RVNAF fighter-bombers from Bien Hoa and Tan Son Nhat flew between 80 and 120 combat sorties per day to support the defenders at Xuân Lộc.

During the meeting with other commanders, Trần Văn Trà decided to alter certain aspects of the attack; the 6th Infantry Division and elements of the 341st Infantry Division would attack Dau Giay, which was the weakest point in the defensive line around Xuân Lộc, set up blocking positions along Highway 2 leading to Bà Rịa–Vũng Tàu, and along Highway 1 between Xuân Lộc and Bien Hoa.

As PAVN commanders began to implement their new strategy, the South Vietnamese military declared it had successfully repulsed the "Communist attack" on Xuân Lộc, thereby ending a period of continuous defeats.

[10]: 173–7 On 15 April, the situation on the battlefield began to change as PAVN artillery stopped their shelling of Xuân Lộc, but started pounding Bien Hoa Air Base instead.

[13]: 181  On the same day, an artillery bombardment of 1,000 rounds fell on the headquarters and 3rd Battalion, 52nd Regiment, an artillery battalion, and elements of the 5th Armored Cavalry Squadron, four 155 mm and eight 105 mm howitzers were destroyed, and the PAVN 6th Infantry Division and the 95B Infantry Regiment defeated a combined ARVN formation which included the 52nd Task Force and the 13th Armored Squadron west of Xuân Lộc.

[8]: 465 [5]: 392–3  On 20 April, under the cover of heavy rain, South Vietnamese soldiers and civilians began pulling out from Xuân Lộc, in a convoy of about 200 military vehicles.

Pro-war elements in the National Assembly argued South Vietnam should fight until the very end, in the belief that the United States would eventually give the country the necessary aid to resist the North Vietnamese.

In his final effort to save South Vietnam, Thiệu gambled his political career by sending the last units of the ARVN to Xuân Lộc in an attempt to hold off the PAVN.