The duo were both coming out of contract from the start of this season, with the Cats handing Neale a two-year extension following his debut campaign of 2022.
Willis is in his second year with the Cats after joining the club as a second-round selection through the 2021 National Draft and has faced a spell of setbacks since swapping South Australia for the Cattery.
The teenager has played nine games at VFL level since the back-end of last year, with his top performance coming last month when he collected 21 possessions and booted three goals.
Geelong list boss Andrew Mackie expressed his delight in having the emerging pair recommit to the club.
“It is fantastic to see James and Shannon both recommit to the Club and remain in the Hoops until 2024 and 2025 respectively, they both have a great work ethic and are exciting prospects,” Mackie said.
“Shannon has shown encouraging signs in the games he's been able to play to this point and we couldn't be happier with the way he has integrated into the Club culture and environment."