The WRU and the four Regions have announced that he is the sixth player to be enrolled as an NDC professional, which secures his future in Welsh rugby.
Ball joins Sam Warburton, Dan Lydiate, Tyler Morgan, Hallam Amos and Rhodri Jones on an NDC with more player signings imminent.
The 23-year-old, who has made eight appearances for Wales since making his debut in the 2014 RBS 6 Nations, will remain a Scarlet in line with the agreed policy of players preferably staying with their Region of origin.
The new National Dual Contracts were agreed as part of the Rugby Services Agreement between the WRU and the four Regions, which was signed last year and operates until 2020.
The WRU holds the primacy of the contracts with players being released for an agreed number of games for their Region.
The Group Chief Executive of the WRU, Roger Lewis, said: “We start the new year with a rugby plan that is clearly working for all of Welsh rugby. I sincerely thank the players for embracing the vision and making it a reality.
“To secure a player of the quality of Jake Ball on a National Dual Contract shows it is our intention to include individuals of proven talent as well as those with enormous potential. Since his selection to the squad he has shown exceptional determination and talent.
“It is vital we take a strategic view and use these NDC’s to future proof the strength of Wales as a force on the international stage while also strengthening the ability of our Regions to compete at the highest level.
“As we add more names to our list of NDC’s it will create a sense of stability which all rugby nations seek to achieve in these times of rapid change and evolution in the professional environment.
“I want the Welsh rugby public to be assured that here in Wales we are developing a structure which offers our best professional talent the security to focus on making the very best use of their talents.”
Ball, who also became a father for the first time over the festive period, said he is delighted to have signed a NDC: “I’m delighted to have signed a National Dual Contract and to be staying in Wales.
“The NDC was a big factor in my decision as I get to work hand in hand with the management at the Welsh Rugby Union as well as the Scarlets.
“Player welfare is extremely important and being looked after by both parties is great for me.
“It’s been a fantastic year for me, I’m still taking everything step by step and want to perform as well as I can for the Scarlets to put my hand up for selection for the Six Nations.”
Wales Head Coach Warren Gatland said: “The signing of Jake on a National Dual Contract is another important step for the future of the game in Wales.
“A player of Jake’s calibre and age attracted serious interest from outside of Wales but the introduction of NDC’s means another Welsh International has committed his future to Wales and his region.”
Scarlets Head Coach Wayne Pivac said: “2014 has been a great year for Jake and we’re excited to see his continued development here at the Scarlets. It’s pleasing to see another of our international players committing to both the region and Welsh rugby”
The WRU Chairman, Gareth Davies said: “It Is fantastic that another prominent Welsh International has signed a NDC and committed their future here in Wales. National Dual Contracts offer players a unique opportunity that will benefit the game at national and regional level.”
