A Japanese submarine will make a port call in the Philippines for the first time in 15 years while accompanying naval ships will visit Vietnam's Cam Ranh Bay for the first time ever, Japan's navy said. The announcement came days after China accused its Asian rival of interfering in the South China Sea.
Japan, which occupied the Philippines and Vietnam during World War II, is now strengthening relations. All three countries share growing concerns about China's increasing military muscle amid a series of maritime disputes.
China claims almost all the South China Sea. It is also embroiled in a separate row with Japan over disputed islands in the East China Sea that has seen relations sour badly in recent years.
Tensions in the South China Sea - through which one-third of the world's oil passes - have mounted in recent months since China transformed contested reefs into artificial islands capable of supporting military facilities.
Brunei, Malaysia, Vietnam and Taiwan also claim all or part of the Spratlys chain in the Sea, while Vietnam and Taiwan have rival claims with China in the Paracels chain there.
The Japanese submarine Oyashio and two escort vessels will visit Subic Bay in the Philippines for annual open sea drills, a spokesman for Japan's Maritime Staff Office confirmed to AFP.