There are unique costumed Pokémon appearing in Pokémon Go during special events throughout the year. You have a limited time to capture these Pokémon before they disappear, with a chance to appear in future events, or to be traded to you with other trainers. They don’t have anything special about them except for the special appearance item around them. For collectors, they want to make sure they have all versions of a Pokémon available to them. The Pikachu wearing an Okinawan Kariyushi shirt you can only capture by visiting Okinawa, Japan.
There’s no catch or special time connected to this Pikachu. Instead, starting on July 22, 2021, you have to be visiting Okinawa, Japan, and make sure to be there at any time before July 22, 2022. The Pikachu in an Okinawan Kariyushi shirt will be available all year long.
The release of this special Pikachu happened alongside the Pokémon Company’s launch of Pokémon Air Adventures, a program designed to create wonderful travel memories for those visiting Japan. Additional Pokémon will be coming out in the same format, and these will also last a year. We don’t believe the Pikachu in an Okinawan Kariyushi shirt will be wandering in the wild outside of Okinawa, Japan. Still, you can likely trade another player who has one in their collection who has visited.