The Maritime Self-Defense Force has announced its participation in joint drills with the Australian navy and air force.
The maneuvers begin next month in the waters off Sydney and will involve one of Japan's Soryu-class submarines.
Wednesday's announcement comes as Japan awaits to hear the outcome of bidding to build Australia's next generation of submarines. Tokyo is widely regarded as the front-runner in the race, with bids from France and Germany also making the final cut of the so-called Competitive Evaluation Process to build the subs.
The exercises are likely to give the Australian side an up-close look at the Soryu-class submarine and its capabilities while also providing a boost for increasingly close ties between the former World War II enemies. A decision on the sub deal is expected this year.
During a visit to Tokyo last month, Australian Foreign Minister Julie Bishop said her country's relationship with Japan was at an "all-time high," and acknowledged that the Japanese side had "emphasized the strategic importance" of the submarine bid.
The joint drills also come amid increased tensions with Beijing over China's land-reclamation projects and maneuvers in the disputed South China Sea.
The United States has conducted what it calls "freedom of navigation" operations near disputed islands in the waters, and has urged both Australia and Japan to also conduct similar operations.