Despite being contracted for this year, Langdon was cut from the Eagles last October after two seasons and 25 games with the Perth club.
The list call ended his five-year stint in the AFL, having first entered the league through the 2017 National Draft as the 56th overall selection.
The Karratha-born forward was swooped on by GWS, where he would play 21 games in his debut season, including two finals appearances.
Injuries and form hampered Langdon's stint with the Giants before the 27-year-old was traded to the Eagles.
The 177cm-tall forward has now found a new home for 2023, with West Perth confirming Langdon's signature on Friday.
"The West Perth Football Club is excited to announce that former West Coast Eagle and GWS Giant Zac Langdon has signed with the Falcons," a club post reads.
"Zac is already looking in incredible condition on the track and will be a welcome addition to the team. Bring on 2023."
His addition to the Falcons will strongly bolster the club's chances of defending their 2022 premiership title, having claimed the flag last year with a 12-point grand final win over Claremont.
Alec Waterman (West Coast), Mitch Crowden (East Perth), Joel Western (Claremont), Kyron Hayden (Subiaco) andTaj Schofield (Subiaco) have also ventured to the WAFL this off-season after leaving the AFL.