The deal comes after Pramac confirmed Zarco’s departure over the Austrian Grand Prix weekend, with Rins’ move announced during the British GP.
Zarco has been a Ducati rider since 2020, when the Italian marque signed him to a deal to join the Avintia satellite squad.
He will move to the Honda team next season, though the Frenchman's team-mate is yet to be confirmed.
Speaking after the announcement, team boss Lucio Cecchinello said: “We are very excited to welcome Johann to the LCR Honda CASTROL team with all the respective details and signatures now in place.
“It is a return to the team after we had some brief time together in 2019, where we could already see his potential and work ethic.
“There are still a lot of races and work to be done this season, but we are looking forward to the start of this new project in 2024.”
Zarco’s stint at Ducati began after he elected to quit his KTM deal a year early during a difficult 2019 season on the RC16 following his switch from Tech3 Yamaha. KTM then parted ways with him with immediate effect after the San Marino GP.
The two-time Moto2 world champion was reticent to join Avintia as he deemed it “not a top team”, but managed a pole position and a podium in 2020 for the squad before being promoted to Pramac on full works-spec Ducati machinery.
Source: Autosport