Scarlets' second row George Earle and hooker Kirby Myhill will join Cardiff Blues at the end of the season.
South Africa-born Earle, 29, joined Scarlets from Super Rugby side Cheetahs on a three-year deal in May 2012 and now qualifies to play for Wales on residency.
He moves despite signing a contract extension with Scarlets in March 2015.
Myhill, 24, rose through the Scarlets' ranks playing for Llanelli and Wales Under-20 on the way.
Blues head coach Danny Wilson coached Myhill in one of his former roles as Scarlets' scrum coach and as a ex-Wales U20 coach.
Wilson said: "Kirby is a talented player of huge potential."
Durban-born Earle has played over 90 games for Scarlets, 13 of them this season after playing for Western Province, Boland Cavaliers, Griquas, and Golden Lions.
|More from BBC Wales Sport|
|Ex-Wales boss Hughes warns FAW over Coleman|
|Swans need three more points for safety - Guidolin|
|Chaz Davies wins again in Spain|
Wilson added: "George is a hard-nosed second row forward who is uncompromising and brings real physicality."
Earle came off the bench for Scarlets as they lost to Blues at Parc y Scarlets in the Pro12 at the weekend.
Cardiff Blues have signed Scarlets fly-half Steven Shingler, Hurricanes centre Willis Halaholo, Bristol back Matthew Morgan for the 2016-17 campaign.
Ulster number eight Nick Williams and Saracens' Wales prop Rhys Gill will also join the club from next season.