The aircraft, in roll-on, roll-off cargo compartment configurations, will be provided as excess defense articles.
Four of the aircraft to be delivered have been recovered from mothball at Section 5 of Davis-Monthan Air Force Base in Arizona, and are now at Hill Air Force Base in Utah for phased maintenance interval regeneration, the U.S. Naval Air Systems Command said.
Regeneration of the first plane is to be completed this year. Regeneration, overhaul and upgrade of each plane will take 10-12 months.
"This FMS sale supports a global strategic initiative for preserving the security and stability of the Asia-Pacific region," said Capt. Michelle Guidry, program manager of the Tactical Airlift, Adversary and Support Aircraft program, which manages Navy and U.S. Marine Corps C-130s.
"We look forward to a continued partnership with the (Japanese military) through the sustainment of their KC-130Rs."
The aircraft are undergoing structural modifications, including replacement of landing gear supports, cargo door supports, center-wing rainbow fittings and corrosion repair.
Thirty overhauled T56-A-16 engines and digital cockpit upgrades are part of the deal.