Simmons, who joined the Club as a 17-year-old in 2021, made his senior debut in 2024 and has gone on to play four times in First-Class cricket for the county.
First team opportunities have been limited for Simmons and he leaves the Club having been a mainstay of the Second XI that won the T20 Cup in each of the last two seasons.
Warwickshire County Cricket Club Head Coach, Ian Westwood, said: “Che is someone who has been a very popular member of our squad and will be greatly missed around the group.
“We wish him the best of luck with Gloucestershire and hope that a fresh start and some luck with injuries can help him fulfil his potential.”
Simmons added: “I’d like to thank everyone at Warwickshire for giving me the opportunity to be part of a great club and for all the support I've received since I first joined the Bears.
“I’m very grateful to all the coaches, teammates, staff and supporters who have played a part in my time at the club and helped me along the way. I’ve made some great friendships and will take away with me a lot of happy memories at the club. I’m thankful to everyone behind the scenes who has played a part in my development on and off the field.
“The Bears hold a special place in my heart.”