[7] In 2019, Simpkin joined the Wynnum Manly Seagulls playing for their Mal Meninga Cup and Hastings Deering Colts sides.

[12] In Round 6, he made his NRL debut for the Wests Tigers, starting at hooker in their 18-14 loss to South Sydney.

[13] Simpkin played a total of nine games for the Wests Tigers in the 2022 NRL season as the club claimed the Wooden Spoon for the first time.

[14] Simpkin played a total of 19 games for the Wests Tigers in the 2023 NRL season as the club finished with the wooden spoon for a second straight year.

[16] Simpkin played six games for Manly in the 2024 NRL season as they finished 7th on the table and qualified for the finals.