The two stars of Pokémon: Let’s Go, Pikachu! and Pokémon: Let’s Go, Eevee! are getting together this summer for a unique Online Competition. In the Let’s Go! Cup, only these two famous Pokémon will be eligible to participate. Registration for the Let’s Go! Cup begins Thursday, July 26, 2018, at 00:00 UTC. All Trainers will need a Pokémon Trainer Club account, a wireless internet connection, and their own Pokémon Ultra Sun or Pokémon Ultra Moon video game with an eligible Pokémon. See the competition regulations for more details. The competition goes from Friday, August 3, 2018, at 00:00 UTC, until Sunday, August 5, 2018, at 23:59 UTC. Trainers will be limited to 10 battles per day. This competition will not have age divisions.
The competition features Single Battles with only one Pokémon, either Pikachu or Eevee, in your party. Pokémon brought in via Poké Transporter are permitted. All Pokémon above and below Lv. 50 will be set to Lv. 50 for the duration of the battles. There are no item restrictions. There will be a 5-minute player clock and 30-second turns. Qualified participants will receive a mobile-sized wallpaper featuring the Pokémon that was selected to battle the most times during the competition. To qualify, players must complete at least one battle. The same competition is also taking place for Pokémon Ultra Sun and Ultra Moon players in Japan.
Source: Pokémon Global Link Japan