The decision was made by the board of the world-famous region last week and has the backing of Llanelli RFC, which will take forward the name of the town in the Premier Division.
The Scarlets region represents the largest geographical area in Wales which includes the development of rugby stretching from Llanelli, through Mid Wales and into North Wales. The Scarlets are equally responsible for a large regional academy for up and coming rugby talent and an extensive community programme with schools throughout their area.
Stuart Gallacher, Chief Executive of the Scarlets said: "Our board has long felt that as the Scarlets represent an area which stretches far beyond the town of Llanelli, we need to reflect that in our name.
"Under the direction of Gareth Jenkins as our Head of Regional Development and Recruitment, we are working hard to ensure the Scarlets regional development programme remains the most comprehensive and proactive in Wales.
"We will always be a major flag bearer for the town of Llanelli - it's our home and that will not change. With a fantastic new stadium here, we will continue to bring visitors from far and wide as well as helping attract investment and commercial opportunities for Llanelli.
"We have been listening to the views of our supporters and discussions with our sponsors and rugby partners across the region about the name change indicate that it has wide support.
"Our brand - 'The Scarlets' is known world-wide and is generally what most people refer to us as today.
"The history and passion of Llanelli rugby club continues in the Scarlets brand and as we close Stradey Park and move to the new stadium, we take that proud tradition with us.
"The move to our new home Parc y Scarlets seemed the most logical time to adopt this change officially as we start a new chapter in our history," said Mr Gallacher.
The 'Scarlets' name already appears on the team kit and some of the region's communications however any appearances of the old 'Llanelli Scarlets' logo will now disappear from the Scarlets website and literature.
President of Llanelli RFC, Derek Quinnell said: "Llanelli and the Scarlets will always be linked in the same breath however you care to look at it. However, the reality is that we need to have two clear identities and I think it will be much simpler for the region to be known as the Scarlets and our premiership side to be Llanelli - it makes sense.
"The name the Scarlets embodies everything that is great about the rugby region as a whole, takes away any confusion and is simpler all round."