On your birthday, go to the Pokémon Center! From Monday, November 1st, 2021, the Pokémon gifts from Pokémon Center Exciting Happy Birthday (ポケモンセンターわくわくおたんじょうび) will be refreshed. Players will now receive a serial code to get one Pinpuku for any one of your: Pokémon Sword or Shield, Pokémon Brilliant Diamond or Shining Pearl, and Pokémon LEGENDS Arceus games! The serial code can be obtained from November 1st, 2021 until October 31st, 2022.

Please come to the Pokémon Center with your Nintendo Switch (or Nintendo Switch Lite) and one of the following games: Pokémon Sword or Shield, Pokémon Brilliant Diamond or Shining Pearl, and Pokémon LEGENDS Arceus.

Furthermore, from November 1st, 2021, Pokémon gifts will be added to the Pokémon Center Online Happy Birthday service.

Information on how to receive the serial code in stores:

・ The present Pokémon will be given to those who own one of the following Nintendo Switch software titles: Pokémon Sword or Shield, Pokémon Brilliant Diamond or Shining Pearl, and Pokémon LEGENDS Arceus. Please bring your Nintendo Switch console (or Nintendo Switch Lite console) and any of the applicable game, and show the game screen to the staff. (Both packaged and downloadable versions can be used.)
・ You will be given a serial code to receive a Pinpuku. You will only be able to receive the gift Pokémon from November 1st, 2021 for Pokémon Sword or Shield, from November 19th, 2021 for "Pokémon Brilliant Diamond or Shining Pearl and from January 28th, 2022 for Pokémon LEGENDS: Arceus.
・ The serial code can only be used once, and cannot be used with any other saved data.
・ Once you receive the serial code for one game, you cannot receive it for any other game. Please be aware of this beforehand.

Source: https://www.pokemon.co.jp/info/2021/10/211022_p01.html

Pokémon Center Singapore Renewal Birthday Gift!

A birthday surprise awaits you at Pokémon Center Singapore starting Monday, 1st November 2021!

Come down and celebrate your birthday with us and receive a Happiny that can be redeemed for Pokémon Sword, Pokémon Shield, Pokémon Brilliant Diamond, Pokémon Shining Pearl or Pokémon Legends: Arceus. Please bring along your Nintendo Switch and show us your game data to redeem a Happiny!

*You will be able to receive your Happiny for Pokémon Brilliant Diamond and Pokémon Shining Pearl from Friday, 19th November 2021 and Pokémon Legends: Arceus from Friday, 28th January 2022.

With our renewed Birthday Service gift, any guests who redeemed their birthday gifts in-store before Monday, 1st November 2021 and have received a Birthday Visit Slip from us will receive Milcery with Star Sweet or Milcery with Ribbon Sweet up to Sunday, 31st October 2021.

Guests who have previously celebrated their birthday with us and received a Birthday Visit Slip will still be receiving Milcery with Star Sweet or Milcery with Ribbon Sweet. Happiny is unavailable for redemption for birthdays before 1st November 2021. For more queries, please do not hesistate to appraoch our friendly staff for more details.

Terms and conditions:

※ Please bring along any form of identification to verify your date of birth. (e.g Identification Card, Student Pass, Passport, Driver's License)
※ Please bring along your Nintendo Switch and the relevant game installed (Pokémon Sword & Shield, Pokémon Brilliant Diamond & Shining Pearl and Pokémon Legends: Arceus) and show the game screen to the trainers to redeem a Happiny. (Both physical or soft copy of the game are allowed)
※ Each gift can only be received once per person during the birthday month.
※ Codes are not for sale, and cannot be reissued even if it's lost, damaged or tampered with.
※ The serial code can be used once per save data per game software.
※ All visit slips with the Pokémon Milcery with Star Sweet or Milcery with Ribbon Sweet obtained before 1st November 2021, will last till 31st January 2022.
※ The contents of the gift may change or end without notice.

Source: https://www.facebook.com/Pokemon.official.Singapore/posts/3024038471256395