Scarlets speedster Darren Daniel got Llanelli off to a great start by speeding 40m to cross in the corner after good lead-up work by scrum half Gareth Davies.
Not to be outdone, Llanelli's other winger, Andrew Fenby, conjured a try from nothing leaving a posse of Aberavon defenders clutching at thin air. Dan Newton converted.
Davies pounced just before the break for the third try although replacement fly-half Jamie Murphy narrowed the gap with a penalty just before the interval and kicked another one soon after.
A penalty by replacement fly-half Luke Richards made it 23-12 and the bonus point was secured when Steve Martin went over a minute from time for a try which Richards converted.