Gavin Henson will join Bristol with immediate effect, with London Irish full-back Tom Homer heading to the Rec.
The former Welsh international was due to join Bristol at the end of the season, but he has been allowed to join the Championship side early by Bath.
Mike Ford's side had lined up Homer as a replacement from next year, but he will also move mid-season, joining the Premiership title contenders from the Exiles.
Ford explained that by allowing Henson to join Bristol early, it made it possible for Bath to bring in Homer and get him settled at his new club.
"Bristol asked if Gavin could join up with them early, and knowing that he wants to get settled there, we were happy to agree to the request," said Ford.
"Gavin leaving has meant Tom can join us straight away, and likewise he can start learning the ropes at his new club."
"Tom is an incredibly talented young player and he's got a great attitude that will fit in well with the squad here and our policy of recruiting young, English talent. He already has a huge amount of experience, given he's only 24, and we're really looking forward to seeing him continue developing as a player here at Bath."
"You can clearly see the ambition, determination and drive that there is at Bath," added Homer.
"There are a lot of talented players at the club and competition for starting places is fierce, but you want that as a player and I can't wait to start training with the squad."
Meanwhile London Irish explained that they were happy to release Homer, with enough full-back cover in the squad to see them through to the end of the season, and Scotland international Sean Maitland set to join from next season.
"Having had a number of meetings with Tom about a new contract, it was clear that he wanted to move on," explained Operations Director Bob Casey.
"We have plenty of cover in the back three with talented players like Andrew Fenby, Alex Lewington and Topsy Ojo so we are able to agree to Tom’s request for early release.
"We have also signed a top class full-back in Sean Maitland for the 2015/16 season. We would like to thank Tom for all he has done for the Club and wish him all the best for the future."