Eardley has agreed a three-year deal to join Blues on July 1 after being released by the Tangerines at the end of the season.
The agreement with the 24-year-old right-back follows similar deals for forwards Lee Novak and Andrew Shinnie and goalkeeper Darren Randolph.
Eardley began his career at Oldham where he made over 100 appearances before moving to Blackpool for an undisclosed fee in August 2009.
He quickly became a mainstay in the Seasiders team that had a one-season stint in the Premier League during the 2010/11 campaign.
The Wales international, who scored a superb goal against Birmingham during a 2-2 draw at Bloomfield Road in November 2011, has 16 senior caps to his name having previously represented his country at Under-17, Under-19 and Under-21 level.