The Russian-born Israeli last raced for Prema in 2021, finishing second in the FIA Formula 2 Championship behind Oscar Piastri.
After several years on the sidelines waiting for a shot in Formula 1, Shwartzman joined AF Corse in GT World Challenge Europe for 2023 before graduating to the FIA World Endurance Championship with the same team in a Ferrari 499P Hypercar.
Shwartzman will join Callum Ilott, who also drove for Prema in his formative years in the now-defunct FIA European Formula 3 Championship.
Shwartzman has been a familiar face in the Formula 1 paddock, having tested for Ferrari, Haas, and Sauber.
He most recently made an on-track appearance with Sauber at the Mexico City Grand Prix where he drove in Free Practice 1 and the Dutch Grand Prix before that.
“I’m definitely very very excited to be back at Prema to start a new adventure in IndyCar,” said Shwartzman.
“Everything will be new to us and there will be many challenges, but it will also be a lot of fun and a lot of work at the same time.
“I think a very successful future lies ahead for us. IndyCar is a very competitive series, with so many strong drivers, and I’m looking forward to the racing, as it looks really cool.
“I have never driven on ovals and to master them, it will be a completely new challenge.
“However, with Prema we achieved a lot in the past, and I think that my F1 and endurance experience will be helpful to make us evolve fast and get up to speed quickly.”
Prema owner Rene Rosin welcomed Shwartzman back to the Italian team.
“We are extremely delighted to welcome Robert back to the Prema family,” said Rosin.
“We have had some exceptional seasons together, winning a lot of races and the 2019 FIA F3 title, and we also thoroughly enjoyed working with him.
“He is an extremely talented driver and I think that, by working together, we will be able to overcome the steep learning curve that lies ahead of us.
“I cannot wait to see him and Callum compete under the Prema banner again.”
The 2025 IndyCar Series gets underway on the streets of St Petersburg on March 1-3.