Scarlets fly-half Gareth Bowen and Blues centre Lee Thomas exchanged penalties in what proved to be a unfulfilling opening quarter for the bumper crowd, keen to prolong the Welsh Grand Slam party.
The opening try of the game arrived on the half hour when prop Phil John went over under the posts after some good work from No.8 Andy Powell.
The Blues bounced back when Thomas grabbed another penalty but the Scarlets wrestled back control of the game with another try before the break.
Ma of the match Powell crashed over from the back of a five metre scrum and the hosts went into the break 17-6 to the good.
The Scarlets reaffirmed their dominance after the break when Bowen added another three-pointer but the Blues once again battled back with a try from through Martin Jones when he got on the end of a drive from a line-out.
The extras came courtesy of Thomas, and he had a chance to narrow the gap even further later in the half but his effort failed with five minutes on the clock.
The result, was assured with another try for the Scarlets through skipper Vernon Cooper which prevented the Blues from gaining a bonus point.
Llanelli Scarlets: Barry Davies; Garan Evans, Matthew Watkins, Salesi Finau, Tal Selley; Gareth Bowen(2C, 2PG), Mike Phillips; Phil John(1T), Matthew Rees, John Davies; Vernon Cooper (capt)(1T), Adam Jones; Chris Wyatt, Gavin Thomas, Andy Powell(1T).
Bench: David Maddocks, Aled Gravelle, Bryn Griffiths, Gavin Quinnell, Chris McDonald, Darren Daniel, Lee Byrne.
Replacements used: G.Quinnell for Wyatt 81.
Cardiff Blues: Nick Macleod; Dean Dewdney, Tristan Davies, Lee Thomas(1C, 2PG), Craig Morgan; Nick Robinson, Ryan Powell; Martin Jones(1T), Gareth Williams, Ben Evans; Craig Quinnell (capt), Deiniol Jones; Maama Molitika, Robin Sowden-Taylor, Kort Schubert.
Bench: Nathan Llewellyn, Rhys Thomas, Nathan Budgett, Nathan Thomas, Richard Smith, Nick Walne, Jonny Vaughton.
Replacements used: Budgett for D.Jones 41, R.Thomas for G.Williams 61, N.Thomas for Molitika 71, Llewellyn for Evans 75.
Scoring sequence: 2' Bowen (PG) 3-0, 14' L.Thomas (PG) 3-3, 28' John (T) 8-3, Bowen (C) 10-3, 30' L.Thomas (PG) 10-6, 38' Powell (T) 15-6, Bowen (C) 17-6, 52' Bowen (PG) 20-6, 60' M.Jones (T) 20-11, L.Thomas (C) 20-13, 78'
Cooper (T) 25-13.
Referee: George Clancy (Ireland). Attendance: 6116.