The TV anime was scheduled to air in April but was postponed due to COVID-19
The official Twitter account for the Sword Art Online TV anime announced on June 10 that the second part of Sword Art Online Alicization War of Underworld has finally got a release date. After solidifying that they were working hard on the series during a live stream and would meet the July scheduled release, it was confirmed that the final season of Sword Art Online Alicization War of Underworld will broadcast from July 11.
The above tweet also announced that an "omnibus" of the story of the first part of Sword Art Online Alicization War of Underworld would be broadcast on July 4 on Japanese TV. The second part will air from July 11 at 24:00 (effectively July 12 at 12:00 AM) on Tokyo MX and affiliated channels.
Aniplex originally announced the next season would air from April 25, before being delayed due to the coronavirus (COVID-19) pandemic. Crunchyroll also originally announced on March 19 that the new season would be coming to the platform.
Source: Sword Art Online on Twitter
Daryl Harding is a Japan Correspondent for Crunchyroll News. He also runs a YouTube channel about Japan stuff called TheDoctorDazza, tweets at @DoctorDazza, and posts photos of his travels on Instagram.