Registration for the 2017 International Challenge May Online Competition has officially started for Pokémon Sun and Moon players. To sign up, log on to your account from the Pokémon Global Link (PGL) homepage and select Online Competitions in the main menu. You’ll then be able to read and accept the regulations on the PGL. You’ll need a Pokémon Trainer Club account, your own Pokémon Sun or Pokémon Moon video game, and a Battle Team of eligible Pokémon. Accept the regulations on the Pokémon Global Link by Thursday, May 25, at 23:59 UTC, and get ready to battle.
The competition goes from Friday, May 26, at 00:00 UTC, until Sunday, May 28, at 23:59 UTC. This competition will use the same rules and regulations as Pokémon Video Game Championship Series events. Participants can earn Championship Points toward an invitation to the 2017 Pokémon Video Game World Championships in August. Additionally, all qualified Trainers who play in at least three battles will earn Tyranitarite, Abomasite, and Manectite Mega Stones, the items needed to make Tyranitar, Abomasnow and Manectric Mega Evolve in battle.
To practice battling for the 2017 International Challenge May Online Competition, go to Festival Plaza in Pokémon Sun or Pokémon Moon, select Battle, and then Download Rules. You can then select the 2017 Championship Series regulations as the rules when you battle with your friends in Festival Plaza or via Quick Link.
Source: Pokémon Global Link