It is yet unsure who will replace Sims at BMW, as current driver Max Guenther confirmed on Tuesday he will stay with the team for a second season next year.
“I’m delighted to be joining Mahindra Racing and continuing my Formula E campaign," Sims told Autosport.
"It is an exciting opportunity to bring on the team’s package and challenge for strong results.
"Promoting sustainability and electric mobility is important to me personally and competing in Formula E provides a strong, innovative and forward-looking platform to raise awareness.
"I want to thank BMW i Andretti Motorsport for all its support during the past two seasons and wish the team well for the future. It’s been a huge learning curve coming into Formula E – it’s such a different discipline in motorsport and brings with it great new challenges.
"I’m excited to continue learning and to use my knowledge to support Mahindra Racing in the upcoming season.”
Mahindra team principal Dilbagh Gill welcomed Sims to the team, saying the team were very excited to begin working with the British driver.
“I’m thrilled on behalf of the whole team to welcome Alexander," Gill added.
"I’m extremely excited about working with him and the prospect of what we can achieve together is motivating.
"In Alexander, we have a proven racing talent plus someone that embodies what Mahindra Racing stands for with his personal principles in the areas of electrification and sustainability.
"He is an intellectual driver, a very nice guy and a team player; I’m enthused about what Season 7 will bring and look forward to announcing Alexander’s teammate in due course.
"At the same time, I would like to pay tribute to Jerome, who leaves us after two years with the team. We have had some great moments together and I wish him all the very best as he moves on to new endeavours. He is a class act and I look forward to seeing what he does next.”
Bahrain International Circuit - Winter testing