Russia-China Submarine Tech Raises Taiwan Alarm

Russia-China submarine tech is drawing fresh alarm after retired Rear Adm. Mark Montgomery warned that Moscow may be helping Beijing make its submarines harder for the U.S. Navy to find. He said the alleged transfer could erode one of America’s most important advantages in any future conflict tied to Taiwan.

Montgomery, a co-author of the book Axis of Aggressors, said Russia is allegedly providing submarine quieting technology to China. He described the issue as a serious threat to U.S. undersea warfare, saying any loss of that edge would matter. Quieting technology lowers a submarine’s acoustic signature, making it more difficult to detect and track. The Navy has long depended on stealth and technical superiority to preserve its undersea advantage, while China has continued trying to improve submarine propulsion and quieting as it modernizes its fleet.

The Chinese Embassy did not directly say whether Beijing has received the technology when asked about the matter. Instead, it said military cooperation between China and Russia follows the principles of non-alliance, non-confrontation and non-targeting of third parties. The embassy added that such cooperation helps protect the sovereignty and security of both countries and supports regional peace and stability. It also said Taiwan is China’s internal affair and urged the United States to protect stability in the bilateral relationship and across the Taiwan Strait.

Montgomery’s warning lines up with concerns raised by Adm. Samuel Paparo, the commander of U.S. Indo-Pacific Command. In April 2025, Paparo told the Senate Armed Services Committee that China was receiving what he called potentially submarine quieting help from Russia. He had voiced a similar concern in November 2024, saying he expected Russia to provide China with submarine technology that could help reduce America’s undersea advantage. Paparo has described the Moscow-Beijing relationship as a transactional symbiosis.