Their two-year deals see them train full-time with Nigel Davies's professional squad as each also pursues educational or vocational studies.
The first Scarlets development contract went to Llanelli RFC lock Aaron Shingler this season. He took the opportunity to break into the first team, making five Scarlets appearances.
Scarlets Head of Regional Development and Recruitment Gareth Jenkins said said: "Jamie, Ben and Rhys are young men with the potential to be very good players for the region. The full-time training they'll have with Nigel Davies's squad means that they have a genuine opportunity to progress to the next stage of their development.
"They will each also be studying for educational or vocational qualifications so that, as well as progressing in rugby, they have an academic or trade base. They will also play a full part in supporting the very busy community programme carried out by the Scarlets - this will involve duties such as visiting schools and coaching children.
"If they progress as we know they can in the next two seasons they will each give themselves a strong chance of becoming a professional in Nigel's squad."
Jamie Corsi Prop, Newport Gwent Dragons
Born in Cardiff on December 30 1987, Corsi stands 6ft 3ins and weighs 17st 5lbs. A specialist tight-head with strong scrummaging ability and a hard work ethic, he has represented Wales at U16, U18, U19 and U20 levels. He toured Australia with the senior Wales squad in 2007 but didn't play due to injury. Educated at Bassaleg Comprehensive School, Newport, in club rugby he has appeared for Bedwas, Cross Keys Ebbw Vale, Newport, Newport High School Old Boys and Pontypool. As part of the Dragons academy in 2006-07, he was called up to the senior side to make his debut against Connacht in October 2006. He was part of the 2006 Grand Slam-winning Wales U19 side and played in every match of the following season's Wales U20s Six Nations campaign, scoring a try against France. He was part of the same Wales U20s squad as Scarlets Rhys Priestland, Ken Owens and Lou Reed. Corsi was a Dragons replacement in the March 2009 friendly victory against the Scarlets at Rodney Parade. He is studying sports development and coaching at Uwic. As well as his Scarlets development contract he has a 2009-10 contract with Llanelli RFC.
Ben Morgan No 8, Merthyr RFC
An influential man with Merthyr RFC in Swalec League One East, Morgan is renowned for his bulldozing runs. He also came to the attention of Parc y Scarlets supporters with five Llanelli RFC appearances this season. Born in Bristol on February 18 1989, he grew up in Kingswood, near Dursley, Gloucs, and played rugby from the age of five for Dursley RFC, captaining the colts in 2005-06 and breaking into the first team as a 17-year-old that season. He spent 2007-08 with Gloucestershire's Cinderford RFC but, having excelled at sevens, was signed by the Merthyr coach Martin Fowler for 2008-09. He also played for Cardiff Blues U20s in their age grade championship side this season, coming to the attention of the England set-up. Representative honours include Gloucestershire U20s with whom he won two consecutive Twickenham finals in the National U20 Championship. Based in Llanelli, he has just completed a plumbing apprenticeship with Pontyberem-based construction firm Lloyd and Gravell and plans to continue his vocational studies. As well as his Scarlets development contract he has a 2009-10 contract with Llanelli RFC.
Rhys Lawrence Hooker, Tonmawr RFC
Born on June 4 1988 in Middlesex, hooker Lawrence stands 5ft 11ins and weighs in at 16st 4lbs. He played for Wales U20s in the age group's 2007-08 Six Nations and World Championships when teammates included Scarlets Josh Turnbull and Jonathan Davies. In March last year the Wales U20s coaching staff praised Lawrence after a man-of-the-match performance in an 11-6 win over Ireland. Coach Patrick Horgan said: "Rhys was brilliant and thoroughly deserved his man of the match award. He was fantastic both in contact and in his ball handling - he was superb." Once with the Ospreys U20s, he has starred in Swalec League Division One West for Tonmawr. He spent his early years in Hillingdon, Middx, and in East Anglia before moving to Swansea and being educated at Olchfa School. Previous clubs include Dunvant juniors and Mumbles youth. Lawrence spent two years working in the prison service and has just completed the first year of his sports science studies at Swansea University. He captained the university's rugby team in this season's traditional Varsity clash with Cardiff University. As well as his Scarlets development contract he has a 2009-10 contract with Llanelli RFC.