STC offensive raised atop a government building in
Seiyun after the offensive On 2 December, a large number of Southern Movement troops started advancing north through the
Sah District, and by the end of the day they were a few tens of kilometres from
Seiyun. The offensive in Wadi Hadhramaut was initiated by the STC's Southern Armed Forces on the morning of 3 December, led by the
Hadhrami Elite Forces. In Seiyun, Southern Transitional Council forces were positioned in the Jathma area, before launching a bombardment against the headquarters of the
1st Military Region and other key targets in the city. The STC followed up the bombardment with a lightning offensive, leaving Yemeni Government forces in disarray. leading to the latter withdrawing its forces. From there, STC forces were able to capture the remainder of Seiyun by nightfall, before proceeding to rapidly advance throughout Wadi Hadhramaut, taking several other towns and military bases. On 3 December, in the
Arma District of
Shabwa Governorate, STC forces claimed they had taken control of "a camp belonging to the
Muslim Brotherhood" in the Arin desert. Southern Transitional Council forces were reportedly seen equipped with Emirati armoured vehicles and Chinese 155 mm
AH4 howitzers, which the UAE has supplied to other proxies. Casualties were also reportedly inflicted on Yemeni forces. though the STC reported the deaths of four of their soldiers in small-scale clashes in the area. In Hadhramaut, Southern forces announced the capture of the 23rd Mechanized Brigade in the
Al Abr area of Wadi Hadhramaut and the 11th Border Guard Brigade at the Rama camp. At the end of the day, the control of Al Abr camp was handed over to the Saudi-backed National Shield Forces. On 4 December, Southern forces seized
Al Ghaydah, the capital of
Al-Mahrah Governorate, without a fight, as well as the
port of Nishtun. Saudi pressure caused the STC to temporarily surrender some of their captured sites; however, STC forces quickly counterattacked and recaptured all those areas almost immediately. On 6 December, the 1st Support and Reinforcement Brigade of Hadrami Elite Forces captured the 315th Armored Brigade's camp in
Thamud district of northern Hadramaut. Meanwhile, the 11th Border Guard Brigade's Ramah checkpoint was captured by the Al-Manahil tribesmen after an attack. Four members of the Giants Brigades were killed when an IED targeted their convoy in
Hadhramaut Governorate. Very little actual resistance to STC advances was reported after the Southern Transitional Council took Seiyun, with Saudi-backed Yemeni Government forces withdrawing in the face of STC advances, and STC forces reportedly secured control of Hadhramaut Governorate roughly 48 hours later. On 7 December, Southern forces entered Al Ghaydah after the sudden withdrawal of the Shield Forces from some positions inside the city. They also took control of the
Sayhut,
Qishn, and
Al Masilah districts in the governorate. By the end of the day they also entered without a fight key coastal and border positions including the Shahn crossing with Oman and the port of Nishtun. On 10 December, Southern forces took control of the west gate of the Ghaydah International Airport while Shield Forces retained control of the airport itself. On 16 December 2025, Southern forces took control of the Nishtun port. On 23 December the National Shield Forces departed the Ghaydah International Airport following pressure from the Southern Transitional Council. By 8 December, STC forces had seized control of most of the regions that were once part of South Yemen, including the entire southern coastline of Yemen, the border region with
Oman, as well as
Dhale Governorate and the oil fields in Hadhramaut Governorate, leaving Yemeni Government forces controlling only the northern reaches of those governorates; the Southern Transitional Council claimed control over all eight governorates on 9 December. By 9 December, STC forces were estimated to control 90–95% of the populated areas in the former South Yemen, in addition to holding at least 80% of Yemen's proven oil reserves. Of all the regions seized by the Southern Transitional Council, the Hadhramaut Governorate was the most strategically valuable one by far, with its control seen as critical for both the Yemeni Government and the STC's secession project.
Saudi–UAE rift In the wake of the STC's large-scale territorial gains, Saudi Arabia amassed troops on their border with Yemen, and on 25 December, they demanded that STC forces withdraw from their recently seized areas in the Hadhramaut and Al-Mahrah Governorates, reportedly threatening airstrikes if they did not. However, STC forces refused to do so. On 26 December,
Saudi Arabia conducted two airstrikes on STC positions in Wadi Nahb in Hadhramaut. The airstrikes followed clashes between the STC and a Saudi-linked tribal leader the previous day. On 27 December, the Saudi-led coalition in Yemen said it would respond militarily to any separatist movements undermining de-escalation efforts in the region, once again calling on the STC to withdraw from the territories it occupied. According to a Yemeni military official, 15,000 Saudi-backed fighters were amassed on the Saudi–Yemeni border, although they had not been ordered into the two eastern governorates of Yemen. On 30 December, a
Saudi-led military coalition supporting
Yemen's current government carried out an airstrike on two vessels from
Fujairah in the
United Arab Emirates which were docked at the port of
Mukalla. According to the coalition, the two Emirati ships had no permits and delivered a large shipment of weapons and
armored vehicles to the
Southern Transitional Council (STC). An STC-aligned journalist reported that the strikes "shattered and damaged the windows of the building near the port." On 31 December, the STC began evacuating deployment sites and partially withdrawing from several locations across Hadhramaut. On 1 January 2026, the STC refused to fully withdraw from the provinces it occupied, though it agreed to the deployment of the Saudi-backed National Shield Forces in those areas.
Yemeni government counter-offensive On 2 January, the PLC chairman
Rashad al-Alimi ordered
Salem Ahmed Said Al-Khanbashi, the governor of Hadhramaut, to assume command of the Homeland Shield Forces in the governorate and begin a military operation to take control of all military bases and camps under STC control. On the same day, the Royal Saudi Air Force conducted air strikes in Al-Khasha and Seiyun, killing at least 20 STC fighters. On 3 January, the military forces aligned with Saudi Arabia issued a statement confirming they had secured all military and civilian facilities throughout Al Mukalla, the main city of Hadramaut. Two government military officials told AFP that Saudi-backed troops had taken control of Al Mukalla's primary military installation. On 4 January, Yemeni forces announced that the Homeland Shield Forces had recaptured all nine districts of Hadhramaut Governorate. The Yemeni government also announced that it had retaken control of Mukalla. Since the beginning of the Yemeni counter-offensive, at least 80 STC fighters were killed, 152 were wounded, while another 130 were captured. Footage showed that government forces retook the city of Mukalla, removing the
Flag of South Yemen that was used by the STC. By late 7 January, Yemeni government forces were reported to be in full control of all districts of
Aden Governorate, including
Aden International Airport and the
presidential palace. On 9 January, Secretary-General Abdulrahman Jalal al-Subaihi announced from Riyadh that the STC would be dissolved. However, STC spokesman Anwar al-Tamimi refuted the decision, stating that only the full council and the president could make such a decision that would be made "immediately upon the release of the Southern Transitional Council delegation currently in Riyadh". On 10 January, the PLC announced that that it had retaken full control of areas previously held by the STC. ==Reactions==