The Pokémon Company has announced the details for the Single Battle Cup competition for Pokémon Sword and Pokémon Shield. Our 8th Generation Online Competitions page has been updated with these details.

Single Battle Cup

Information
Region: International Registration Period: June 10th, 2022 until June 23, 2022, at 4:59 p.m. PDT Tournament Period: June 23, 2022, at 5:00 p.m. to June 26, 2022, at 4:59 p.m. PDT, Ranking Results Announcement: July 2022 Compatible Games: Pokémon Sword and Pokémon Shield Eligible Pokémon: Ranked Battles Series 9 - All Pokémon from the Galar Pokédex, the Isle of Armor Pokédex, and the Crown Tundra Pokédex, excluding the following Pokémon: Mewtwo, Lugia, Ho-Oh, Kyogre, Groudon, Rayquaza, Dialga, Palkia, Giratina, Reshiram, Zekrom, Kyurem, Xerneas, Yveltal, Zygarde, Cosmog, Cosmoem, Solgaleo, Lunala, Necrozma, Zacian, Zamazenta, Eternatus, Calyrex Battle Type: Single Battles Entry Gift: Qualifying players who participate in at least one battle during the event will receive 50 BP whether they win or lose.
In this in-game competition, you can take on Trainers from around the world using the Ranked Battles Series 9 regulations, which means that Mythical Pokémon and the more powerful Legendary Pokémon are not permitted in battle. Put together a team without any of these restricted Pokémon and prepare to show off your skills!

Register Now for the Single Battle Cup Competition

Challenge Pokémon Sword and Pokémon Shield players from around the world to earn BP.

Registration is now open for the Single Battle Cup in Pokémon Sword and Pokémon Shield. In this in-game competition, you can take on Trainers from around the world using the Ranked Battles Series 9 regulations, which means that Mythical Pokémon and the more powerful Legendary Pokémon are not permitted in battle. Put together a team without any of these restricted Pokémon and prepare to show off your skills!

Qualifying players who participate in at least one battle during the event will receive 50 BP whether they win or lose.

You can register from now until June 23, 2022, at 4:59 p.m. PDT. To register for the competition, follow these steps:

1. Launch your Pokémon Sword or Pokémon Shield game.
2. Open the X menu.
3. Select VS.
4. Select Battle Stadium.
5. Select Online Competitions.
6. Select Search Official Competitions.

The competition takes place from June 23, 2022, at 5:00 p.m. to June 26, 2022, at 4:59 p.m. PDT, so don't forget to return during that time to play your matches. Follow these steps to receive your Participation Gift:

1. After the competition has ended, launch your Pokémon Sword or Pokémon Shield game.
2. Open the X menu.
3. Select Mystery Gift.
4. Select Get a Mystery Gift.
5. Select Get Battle Stadium Rewards.

Good luck competing in the Single Battle Cup, Trainers!

Source: https://www.pokemon.com/us/pokemon-news/register-now-for-the-single-battle-cup-competition/