Lamont has won 37 caps for Scotland since his debut in 2004
Scotland winger Sean Lamont has signed a three year deal to join the Scarlets from Northampton Saints.
The 28-year-old spent four years with the Saints scoring 23 tries in 68 appearances.
But Perth-born Lamont has spent much of the last two years on the injury list, most notably a serious knee injury.
"I'm now ready for a fresh start and a new chapter with the Scarlets at this imposing stadium and look forward to making an impact," said Lamont.
"There's great passion for the sport in Wales, especially across the Scarlets region.
"So I can't wait to get going and join up with a great group of players and such a well-known rugby club with proud traditions.
Scarlets head coach Nigel Davies said: "We've had our eye on Sean for some time.
"He'll bring pace, great power and considerable skill to our backs unit.
"He fits well into our set-up, will have an impact on the field and help raise the game of some of our younger players.
"We are really pleased he is joining us."
Lamont won the Scotland player of the season award in 2007 and in 20 club appearances this season, he has touched down six times.
One of those tries came in November's EDF Energy Cup victory over the Scarlets at Franklin's Gardens.
His international career has brought seven tries, his latest cap coming against Wales in this season's Six Nations in February 2009 at Murrayfield.
"He's been fantastic for us recently, playing really well," Northampton boss Jim Mallinder said last week.
"But it's one of those things. When players come out of contract they get offers from elsewhere."