According to LIVE JAPAN, ANA will soon be launching JP ¥2020 ($20) domestic fares for foreign visitors. Travel dates fall from 1st July to 30th September.
Details on ANA JPY 2020 Domestic Fares
ANA has been running a “Discover JAPAN Fare” promotion for foreign visitor and it was said that the prices published on “Discover JAPAN Fare” will be further slashed down to JP ¥2020 ($20) for travel during 1st July to 30th September. Do note that this JP ¥2020 ($20) promotion is not yet active at the moment.

This JP ¥2020 ($20) fare will be applicable for domestic flights to and from the Tohoku Region (Aomori, Odate Noshiro, Akita, Shonai, Sendai and Fukushima airport). Foreign visitors may fly in from major airports like Tokyo or Osaka.

Similar Promotion Offered by Japan Airlines
Earlier in December 2019, Japan Airlines announced that they are giving out free domestic tickets for 50,000 passengers. Travel period also falls from 1st July to 30th September. In case you missed this promotion, you can read up more details in the post below. This free domestic ticket promotion is not yet active at the moment either.
H/T: LoyaltyLobby