Wales internationals George North, Rhys Priestland, Tavis Knoyle, Rob McCusker and Josh Turnbull have all signed contract extensions at the Scarlets.
The quintet are five of 21 Welsh qualified players that the Llanelli region have secured on new deals for at least another two seasons.
English-born number eight Ben Morgan, tipped as a future Wales international, has also agreed an extension.
Coach Nigel Davies says it shows their commitment to back home-grown talent.
"It was crucial and a key objective for our future rugby ambitions and goals to have retained such a strong core of players at Parc y Scarlets and is a hugely positive step for us next season and beyond," he said.
"We're delighted to have retained a number of key impact players who are committed for the forthcoming seasons to the Scarlets, our style of rugby and our identity and culture.
"It underpins the investment and progress that is being made in development of great Welsh talent from within our region and comes just two days after we fielded an all Wales starting XV on Sunday against Treviso.
"Our philosophy of putting our belief and faith in young rugby players discovered, nurtured and developed from within our own system, has shown itself to be of value and purpose.
"This season we've already seen an increasing number of our Scarlets picked for international duty.
"A total of 29 of our players were on international duty at U18, U20 and senior Wales levels during the Six Nations - a source of real pride for all those working within our region and supporting us."
The full list of players who have committed themselves to two and three year contracts for the coming seasons are: Aaron Shingler, Morgan, Damian Welch, Dan Newton, Emyr Phillips, Morgan Stoddart, Peter Edwards, Phil John, Gareth Maule, Johnathan Edwards, Scott Williams, McCusker, Knoyle, Aled Davies, North, Turnbull, Priestland.
Development contracts have been given to Dale Ford, Kirby Myhill, Jordan Williams and Rhodri Jones.