In June 2011, Vietnam announced that its military would conduct new exercises in the South China Sea.
China had previously voiced its disagreement over Vietnamese oil exploration in the area, stating that the Spratly Islands and the surrounding waters were its sovereign territory.
Defense of the South China Sea was cited as one of the possible missions of the first Chinese aircraft carrier, the Liaoning, which entered service in September 2012.

In October 2011, Nguyễn Phú Trọng, the General Secretary of the Communist Party of Vietnam, made an official visit to China at the invitation of General Secretary of the Communist Party of China Hu Jintao with the aim of improving relations in the wake of the border disputes.
However, on 21 June 2012, Vietnam passed a law entitled the "Law on the Sea", which placed both the Spratly Islands and the Paracel Islands under Vietnamese jurisdiction, prompting China to label the move as "illegal and invalid."
Simultaneously, China passed a law establishing the prefecture of Sansha City, which encompassed the Xisha (Paracel), Zhongsha, and Nansha (Spratly) Islands and the surrounding waters.
Vietnam proceeded to a strong opposion to the measure and the reaffirmation of its sovereignty over the islands.
Other countries surrounding the South China Sea have claims to the two island chains, including Taiwan, Brunei, Malaysia, and the Philippines, but the conflict remains predominantly between Vietnam and China.

In May 2013 Vietnam accused China of hitting one of its fishing boats, and in May 2014, Vietnam accused China of ramming and sinking a fishing boat.
Indeed, in recent years, Beijing oversaw the replacement of traditional Chinese wooden fishing vessels with steel-hulled trawlers, fitted with modern communication and high-tech navigation systems.
The better-equipped boats sailed into the disputed waters as a state-directed effort to extend Chinese sovereignty, while in Vietnam, private citizens, not the government, would donate to Vietnamese fishermen to maintain their position in the South China Sea and to defend national sovereignty.
That dynamic continues to be a major source of tension between the two countries.

In June 2014, China declared there would be no military conflict with Vietnam as the two were sparring over an oil rig in disputed territory in the South China Sea.
China then had 71 ships in the disputed area, and Vietnam had 61.

However, on 2 June 2014, it was reported by VGP News, the online newspaper of the Vietnamese Government that the previous day, Chinese ships had in three waves attacked two Vietnamese Coast Guard ships, a Vietnamese fisheries surveillance ship and a number of other ships by physically ramming the ships and with water cannons.

In 2017, Beijing warned Hanoi that it would attack Vietnamese bases in the Spratly Islands if gas drilling continued in the area.
Hanoi then ordered Spain's Repsol, whose subsidiary was conducting the drilling, to stop drilling.

Through 2019 and 2020, Chinese ships have continued attacking and sinking of Vietnamese fishing and other vessels in different incidents.

In May 2020, an Israeli cybersecurity company reported to have discovered ransomware attacks targeting government systems in Vietnam and several other countries by China linked groups.

According to the Council on Foreign Relations, the risk of a military confrontation between China and Vietnam is rising.

It was reported by VOA on 27 August 2020 that a U.S. defense official said that “ The People's Liberation Army (PLA) launched four medium-range ballistic missiles from mainland China into an area of the South China Sea between Hainan Island and the Paracel Islands.”
Vietnam has protested the exercises.
In June 2011, Vietnam announced that its military would conduct new exercises in the South China Sea. China had previously voiced its disagreement over Vietnamese oil exploration in the area, stating that the Spratly Islands and the surrounding waters were its sovereign territory. Defense of the South China Sea was cited as one of the possible missions of the first Chinese aircraft carrier, the Liaoning, which entered service in September 2012.
In October 2011, Nguyễn Phú Trọng, the General Secretary of the Communist Party of Vietnam, made an official visit to China at the invitation of General Secretary of the Communist Party of China Hu Jintao with the aim of improving relations in the wake of the border disputes. However, on 21 June 2012, Vietnam passed a law entitled the "Law on the Sea", which placed both the Spratly Islands and the Paracel Islands under Vietnamese jurisdiction, prompting China to label the move as "illegal and invalid." Simultaneously, China passed a law establishing the prefecture of Sansha City, which encompassed the Xisha (Paracel), Zhongsha, and Nansha (Spratly) Islands and the surrounding waters. Vietnam proceeded to a strong opposion to the measure and the reaffirmation of its sovereignty over the islands. Other countries surrounding the South China Sea have claims to the two island chains, including Taiwan, Brunei, Malaysia, and the Philippines, but the conflict remains predominantly between Vietnam and China.
In May 2013 Vietnam accused China of hitting one of its fishing boats, and in May 2014, Vietnam accused China of ramming and sinking a fishing boat. Indeed, in recent years, Beijing oversaw the replacement of traditional Chinese wooden fishing vessels with steel-hulled trawlers, fitted with modern communication and high-tech navigation systems. The better-equipped boats sailed into the disputed waters as a state-directed effort to extend Chinese sovereignty, while in Vietnam, private citizens, not the government, would donate to Vietnamese fishermen to maintain their position in the South China Sea and to defend national sovereignty. That dynamic continues to be a major source of tension between the two countries.
In June 2014, China declared there would be no military conflict with Vietnam as the two were sparring over an oil rig in disputed territory in the South China Sea. China then had 71 ships in the disputed area, and Vietnam had 61.
However, on 2 June 2014, it was reported by VGP News, the online newspaper of the Vietnamese Government that the previous day, Chinese ships had in three waves attacked two Vietnamese Coast Guard ships, a Vietnamese fisheries surveillance ship and a number of other ships by physically ramming the ships and with water cannons.
In 2017, Beijing warned Hanoi that it would attack Vietnamese bases in the Spratly Islands if gas drilling continued in the area. Hanoi then ordered Spain's Repsol, whose subsidiary was conducting the drilling, to stop drilling.
Through 2019 and 2020, Chinese ships have continued attacking and sinking of Vietnamese fishing and other vessels in different incidents.
In May 2020, an Israeli cybersecurity company reported to have discovered ransomware attacks targeting government systems in Vietnam and several other countries by China linked groups.
According to the Council on Foreign Relations, the risk of a military confrontation between China and Vietnam is rising.
It was reported by VOA on 27 August 2020 that a U.S. defense official said that “ The People's Liberation Army (PLA) launched four medium-range ballistic missiles from mainland China into an area of the South China Sea between Hainan Island and the Paracel Islands.” Vietnam has protested the exercises.  
China–Vietnam relations