The 38-year-old former England striker left Preston over the summer when his two-year contract expired after leading them to promotion to the Sky Bet Championship last season following a career which saw him score 150 goals in 820 appearances.
He posted on his Twitter account on Friday a photograph of a pair of hanging football boots with the words: "It's been emotional
Thank you to everyone who has helped me along the way #22seasons."
Davies began his career in the Sheffield United academy before making his professional debut for Chesterfield in 1993, with two stints at Southampton either side of a spell at Blackburn
The Sheffield-born forward then made the move to Lancashire neighbours Bolton, where he enjoyed a 10-year stay as he racked up more than 350 appearances and scored 74 goals
From there Davies joined North End in his last career move
He told BBC Radio 5 live: "I could probably physically do another season but I just feel it's the right time
"I'll look back with immense pride for the last 22 years."
In 2010, Davies - a t 33 years and 200 days - became the oldest England debutant since 38-year-old Leslie Compton in 1950 when he came on as substitute in a Euro 2012 qualifying game against Montenegro, his only cap
Davies says the call-up was the high point of his career, adding: "I'd been in so many of those long squads and on stand-by I never thought it would quite come
"To get the call at 33, it was just an amazing week for myself
I just loved every minute, travelling down, the training and getting on to the pitch.
"It wasn't a great game, to get on the pitch and represent my country was the pinnacle."
Source : PA
Source: PA