Registration for the 2017 International Challenge May officially begins on Wednesday, May 17, 2017, at 00:00 UTC. The sign-up period will run through Thursday, May 25, 2017, at 23:59 UTC – while the actual competition is scheduled to go from from Friday, May 26, at 00:00 UTC, until Sunday, May 28, at 23:59 UTC. Pokémon Sun and Moon players will compete using the 2017 Championship Series format, featuring Double Battles with Pokémon found in the Alola Pokédex. Zygarde, Cosmog, Cosmoem, Solgaleo, Lunala, Necrozma and Magearna cannot be used. Mega Stones are not allowed as well. For complete details on this Online Competition, click here.