Outside half Jones, who has scored 917 points in 104 internationals for Wales, will move to England after 15 years commitment to rugby in West Wales.
The experienced 34-year-old, who has also played in six Tests for the British & Irish Lions, has appeared in 313 matches for the Scarlets, scoring 2850 points to date.
"I feel this is the right time to move on at this stage in my rugby career - the Scarlets are showing such promise and have plenty to build on for the future with a very talented group of emerging players who are only going to go from strength to strength now," said Jones.
"I feel very privileged to have been part of this great club for so many years and particularly the new era - with a team that now has so many exciting new players coming through and achieving international honours. I hope I've been able to pass on some of my experience for the benefit of our future as a region and helped accelerate the transition of this squad in recent years.
"It's been a huge part of my life being a Scarlet - starting when I was 18 and now leaving when I'm 34 and apart from a couple of years in France its where I've grown up as a rugby player. I've been delighted to be part of Scarlets rugby throughout and it has been an honour to pull on the shirt every single time.
"It's going to be difficult to leave but I know this is the right time. It has been an ambition of mine to play in England at some point in my career and I look forward to a new and exciting challenge ahead by joining Wasps."