The "Pohang-class corvette" will be decommissioned by the end of the year and donated to the Philippines, the Department of Foreign Affairs in Manila said in a statement issued this week.
It was unclear if the donation would include the ship's weapons systems.
South Korean Defence Minister Kim Kwang-jin informed his Filipino counterpart Voltaire Gazmin of the donation during his visit to Seoul on May 30, the statement added.
The gift follows South Korea's recent donation of a landing craft and 16 rubber boats to the Philippines, it added.
"South Korea's gesture is a small token compared with the great contribution of Filipino troops during the Korean War," the South Korean minister was quoted as saying.
Officials at the Manila's foreign ministry and the South Korean embassy could not be contacted for comment.
The donation comes as the Philippines is facing increasing pressure from China over their conflicting claims to the South China Sea.
China claims most of South China Sea even up to the coasts of its neighbours and the Philippines has increasingly accused its larger neighbour of using bullying tactics to enforce its claim.
The Philippines, which has one of the most poorly-armed militaries in the region, has been upgrading its defence capabilities in recent years.
It has also been improving its defence relations with South Korea and in March, it signed an agreement to buy 12 South Korean-made FA-50 jets for about $421.12 million.