The 25-year-old has agreed a three-year deal after spending the second half of 2021-22 on loan at Bournemouth.
Manager Ryan Lowe told the club's website: "We were aware Freddie wanted a new challenge and I'm really pleased we've got it done.
"We've beaten off some competition for Freddie as he's seen what we're trying to build here at Preston North End.
"We feel he's going to be one of the best goalkeepers in the Championship.
"His attributes are playing out from the back and his goal saving of course, so he'll be a top player for us and we're really excited to start working with him.
"Marshy's [Mike Marsh] worked with him before with England and with Swansea for two seasons, so when he's telling you to sign him it becomes a no brainer."