The Championship club left Ealing at the end of the 2020 season after being told the ground is no longer fit to host Super League matches and with the intention of moving in with AFC Wimbledon at Plough Lane.
The Broncos are still waiting for Dons fans to agree to the ground-share and, in the meantime, will play at Rosslyn Park, starting with Saturday’s Challenge Cup first-round tie against Keighley.
However, the club have also announced a short-term agreement to play home Championship games at the Trailfinders once crowds are permitted to return from May 17.
London chief executive Jason Loubser said: “Once we received the news that our proposed move to Plough Lane would only be possible following a couple of key processes, I spoke with Shaun (Justice) at Trailfinders Sports Club about the possibility of returning to Vallis Way to play our games in the Betfred Championship.
“Trailfinders have always been great to work with and the whole team were very keen to do everything they could to make it possible which was brilliant for us.”
Shaun Justice, of Trailfinders Sports Club, said: “Our relationship with the London Broncos has always been strong and we are delighted to work with them on a short-term basis in these turbulent times.”