The Avenger-class ships are the USS Pioneer and USS Chief. They will be based in Sasebo, Japan, and replace the USS Avenger and USS Defender which have been serving since 1987, the Navy reported.
Avenger-class vessels are minesweepers with advanced sensor systems,. They are 224 feet long, displace 1,312 tons and have a speed of 14 knots.
The Navy said the two ships on their way to Japan have newer capabilities than those they are replacing.
"Pioneer and Chief will bring improved capability on newer platforms to the Western Pacific and reinforce the U.S. Navy's mission of maintain safe and free navigation of the seas," the Navy said. "Built to detect, identify, and neutralize underwater mine threats, the ships represent a commitment to peace and stability in an increasingly vital region.
"... These ships will regularly operate with their counterparts in the Japan Maritime Self Defense Force, further strengthening and deepening the alliance. The valuable alliance is fostered through Japans long-term commitment and hospitality in hosting U.S. forces as well as frequent combined operations."
The vessels are being carried to Japan aboard an ocean-going heavy-lift ship