Two Maritime Self-Defense Force vessels, carrying about 700 troops and a medical team, left the Kure naval base in western Japan on Monday to join relief efforts in the typhoon-hit Philippines.
The Osumi transport vessel and Ise escort vessel are scheduled to arrive near the island of Leyte around Friday along with the Towada supply vessel, which left Japan a day earlier.
The three vessels will be used to provide medical services, prevent epidemics and transport relief supplies.
"The situation might be severe over there, and we'll do our best," said Hisanori Sato, commander of the dispatch.
The death toll from Typhoon Haiyan has risen to 3,976, with 1,598 people reported missing, according to the Philippine government's central agency for disaster management.