The 62-year-old is swapping the Ford Raptor T1+ he drives for the Ford M-Sport squad in the FIA World Rally-Raid Championship for a Fiesta Rally2 on the ERC season-opening 42nd Rally Sierra Morena - Córdoba Patrimonio de la Humanidad.
Sainz scored seven wins in 24 ERC starts before going on to take the FIA World Rally Championship by storm with two WRC titles and 26 victories during a standout stage rallying career.
He will partner Jon Armstrong in the expanded M-Sport Ford World Rally Team line-up for what’s expected to be a one-off comeback.
Iain Campbell, the ERC championship manager, said: “We’re delighted to welcome King Carlos back to the ERC and there’s no better way to celebrate 1 April than with this excellent news.
“There have been a few logistical and administrative challenges to overcome but to have one of the world’s greatest rally drivers of all time competing on round one of the 2025 ERC season will make it all worthwhile.
“We’re interested to see what he’ll make of the strong competition in the ERC, including from Jon Armstrong, his team-mate for the weekend. But we wish him the best of luck.”
Sainz has registered for the new-for-2025 FIA Master ERC Championship, which features ex-Formula One driver Jos Verstappen among the entry.
The 42nd Rally Sierra Morena - Córdoba Patrimonio de la Humanidad is based in Córdoba from 3 - 6 April.