The "Brave Blossoms" will take on the world's sixth-ranked team in Osaka on June 8 and in Tokyo on June 15.
Japan coach Eddie Jones insisted his side needed more games against top opposition in order to stand any chance of improving on their wretched run of results at World Cups.
"We need more quality games against the world's biggest teams to achieve our goal of getting into the top 10," Jones said..
"We'll have Wales and then games with the islands (Fiji and Samoa) and Canada next year, so those are good tests but we need to keep plugging away.
"When you're at the bottom of the food chain all you can do is keep asking and keep sticking your hand out."
Japan's one World Cup victory in 24 matches came against Zimbabwe in 1991. They are currently ranked 16th in the world.
"There is a big gap between the level of rugby played in Japan and international rugby," Jones was quoted as saying by Japan's Kyodo news agency.
"These two Tests are so important. But two are not enough. You can't play low level teams and improve. We need 10 games like this a year."
Wales last played in Japan in 2001, when they swept a two-Test series after suffering an embarrassing defeat by Suntory in their opening tour game.