The Cherries could be about to make a double swoop for the defensive pair in a £15 million raid.
The release of Sylvain Distin and the sale of skipper Tommy Elphick to Championship outfit Aston Villa has left the Cherries with limited defensive options for the coming season, and boss Eddie Howe has identified the R's pair as an ideal fit.
Caulker looks set to be moved on from QPR
Caulker has not played for the Loftus Road outfit since May 2015, with the club understood to be looking at moving him on in a bid to get his £40,000 wages off the books.
Bournemouth made a bid to sign the 24-year-old last summer, only to be snubbed in favour of a move to south coast rivals Southampton.
Bournemouth a successful first season in the Premier League
However, he endured a difficult spell at St Mary's and left in January, before earning a surprise six-month loan at Liverpool.
Onuoha could be tempted by a move to the Premier League
Meanwhile, former Manchester City defender Onuoha played a key part for QPR last season after being made captain last summer, but may well be tempted by a return to the top flight.
It has already been a busy summer for Bournemouth, having already brought in Lys Mousset, Nathan Ake, Lewis Cook and Emerson Hyndman.