Band together with your fellow Trainers in global missions: limited-time events where everyone tries to meet a collective goal. If the goal is met, everyone who participated gets a global mission reward! Don’t worry if the goal isn’t reached—you can count on a global mission participation prize for everyone who chipped in.
Follow these steps to join the global mission:
1. Enter Festival Plaza in Pokémon Ultra Sun or Pokémon Ultra Moon by selecting it in your in-game menu, which you’ll find by pressing the X Button.
2. Enter Festival Plaza’s central castle.
3. Speak to the global mission receptionist on the right and let her know you want to participate in the global mission.
4. Remember to return before the mission ends to sync your game to add to the global count! Once you’ve joined the global mission, talk to the receptionist to have your progress sent to the Pokémon Global Link. Also, if you’ve registered your game to a PGL account, simply connecting to the internet while in Festival Plaza will cause your game to sync automatically, sending your progress to the server.
How to check your progress toward the global goal
Talk to the receptionist to check on the overall progress toward the goal and to update your own progress as well. You can also check on the progress by visiting the home page of the Pokémon Global Link.
Pokémon Ultra Sun and Pokémon Ultra Moon Global Mission Schedule
November 17–28, 2017: Catch a lot of Pokémon!
December 12–27, 2017: Have Fun Mantine Surfing!
January 9–23, 2018: Win at the Battle Agency!
February 6–20, 2018: Harvest Poké Beans!
March 6–20, 2018: Trade Pokémon at the GTS!
April 3–17, 2018: Hatch a lot of Eggs!
May 1–15, 2018: Get BP at the Battle Tree!
June 5–19, 2018: Play in Festival Plaza!
Source: Pokémon Global Link