All three both played in Wales’ 25-7 win against Ireland on 16 March and were key members of the Scarlets side which won the Pro12 at 20 17.
“I am delighted that Rob, Ken and Jon have re signed to the Scarlets,” said coach Wayne Pivac.
“They’ve been a major component of our success in recent decades. It is excellent news for the Scarlets.”
Regional captain Owens and center Davies, 30, are both British and Irish Lions, together with Davies named man of the show because the Lions drew 11 with newzealand at 20 17.
Evans, 26, has made 35 appearances for Wales, for example four throughout the 2019 Six Nations Grand Slam campaign.
“I could not be happier to be staying with an Scarlets,” said Davies, who has played 154 matches to the Scarlets since making his debut in August 2006.
“I am excited about the end of the season and having spoken to our newest trainer Brad (Mooar), worked up about what is in the future.”
Hooker Owens, 32, was captain since 2014, and made his 64th appearance for Wales against Ireland.
The statement comes two weeks after a projected merger of Ospreys and Scarlets collapsed.