The 24-year-old, sidelined since late-January with a shoulder injury, scored 64 goals in 57 Dolphins appearances before spending time at Swindon and Burnley.
Loftus Road boss Harry Redknapp, who steered Cherries to their highest finish in the second tier, confirmed the hitman was available.
He said: “Charlie is a tough sort, he loves playing and it will be great to have him back.”
Prior to his injury, Austin was in fine form, with 15 goals in 28 appearances making him top scorer for the Rs.
Less positive news for Redknapp is that midfielder Joey Barton and defensive duo Nedum Onuoha and Aaron Hughes are ruled out.
With a glut of ex-Premier League players on their books and plenty of financial resources, QPR still have an outside chance of automatic promotion, but Cherries midfielder Harry Arter feels the London club are not as well off as they might be.
Arter told the Daily Echo: “They were expected to go up automatically and were probably clear favourites for the league.
“You’ve only got to look at their manager, who is one of the best managers in England and has achieved so much in his career.
“With him in charge and the players they have got there, you would have expected them to be at the top.
“The Championship is a really difficult league and maybe their fans didn’t understand that. Maybe the fans thought they would walk it, but things don’t always go to plan.”