The submarine entered the port to replenish supplies during an operational deployment, with the port call coming against the backdrop of increased military coordination between the United States and South Korea, the ROK Navy said.
"With the visit of USS Annapolis, the navies of South Korea and the US plan to strengthen joint defense and hold exchange activities to celebrate the 70th anniversary of South Korean-American alliance," the South Korean Navy said.
The USS Annapolis arrived in South Korea just days after another US nuclear submarine left the Port of Busan.
Last week, the USS Kentucky, an Ohio-class nuclear ballistic missile submarine, made port in Busan in southeastern South Korea. The same day, the meeting of the two countries' Nuclear Consultative Group (NCG) was held, where South Korean President Yoon Suk-yeol and US President Joe Biden reaffirmed their commitment to "deter" North Korea.
North Korean Defense Minister Kang Sun Nam slammed the USS Kentucky's deployment, saying that Pyongyang could potentially consider it a sufficient basis for the use of nuclear arms for self-defense.
Washington and Seoul agreed on the deployment of nuclear-powered and nuclear-armed US submarines in South Korea in April, during President's Yoon's visit to the US. Before this year, US ballistic missile submarines armed with nuclear weapons hadn't visited South Korea since 1991.
Tensions on the Korean Peninsula have ramped up dramatically over the past two years, with carefully-arranged agreements between North Korean leader Kim Jong-un and his South Korean and US counterparts Moon Jae-in and Donald Trump on easing regional tensions collapsing dramatically under the latter two leaders' successors, Yoon and Biden.
The ramping up of US-South Korean drills has prompted North Korea to dramatically escalate its long-range ballistic and cruise missile testing, and to unveil a new nuclear doctrine last fall in which Pyongyang officially declared itself a nuclear power. The Pentagon has recognized the growing power of North Korea's nuclear and missile capabilities. Last week, US Indo-Pacific Command chief Admiral John Aquilino said Pyongyang has missiles which the US assesses "could reach the United States."