The English lock has spent the last two years with the French Top 14 club and will move to Murrayfield in the summer.
Born in Middlesbrough, Phillips, 28, came through the ranks at the Leeds Tykes academy and then joined Darlington Mowden Park. He signed for Championship club Jersey Reds in 2014 before moving to Aviva Premiership side Worcester Warriors three years later.
At 6ft 8in and weighing 119kg, Phillips offers plenty physical presence and Edinburgh coach Richard Cockerill said: “We’re really pleased to sign Pierce. He’s a quality, experienced player with an excellent physical profile for the position, as well as being a really good fit for our squad as someone who’ll be available to us all season long.
“We’ve good strength and depth in the second-row, with several Scotland internationalists and those with credible Scotland ambitions.
“Having the right balance is essential if you’re to have genuine play-off ambitions in domestic and European Cup competitions. Hopefully he’ll help us achieve that in the seasons to come.”
Phillips played against Edinburgh in the 2019-20 Challenge Cup and liked what he saw.
“I was quite impressed at the time with how they were organised,” he said.
“It’s a team that’s well coached and has a lot of talented players to go alongside that, so I’ve a good feeling it’ll be a great place for me to improve myself and be a part of a group trying to achieve good things.