A brace of first-half tries from lock Sean Duggan and winger Aaron Carroll set the All-Ireland League Division 1A leaders on their way to repeating their Charity Cup final success of last season over great rivals Shannon.
Young Munster had recovered from the concession of a seventh-minute try to Shannon flanker Emmet McLoughlin to lead 15-7 at the break.
It was the third Young Munster try, from replacement Darragh Payne on the hour, that finally broke Shannon’s plucky resistance.
Out-half Willie Staunton kicked 10 points for Young Munster, while his opposite number Tadhg Bennett landed eight points with the boot.
Despite the absence of several first choice players from both sides, the teams served up a competitive and entertaining decider.
Scorers for Young Munster: Tries: S Duggan, A Carroll, D Payne. Pens: W Staunton (2). Cons: W Staunton (2).
Scorers for Shannon: Try: E McLoughlin. Pens: T Bennett (2). Con: T Bennett.
YOUNG MUNSTER: M Costello; C O’Hanlon, M Doyle, A Burke, A Carroll; W Staunton, B Haugh; G Flaherty, G Burke, H McGrath; S O’Neill (capt), S Duggan; J Moroney, J O’Neill, N Melbourne.
Replacements used: G Slattery, D Murphy, D Payne, S Hassett, D O’Neill, D Bannon.
SHANNON: G Quinn-McDonogh; R Mullane, M Lawler (capt), A Spring, D O’Donovan; T Bennett, A Bennie; L Hogan, J Deegan, K O’Neill; K Hanley, D Heffernan; E McLoughlin, J Murphy, J Sheerin.
Replacements used: J Randles, G McNamara, L Mullane, S McNamara.
Referee: Jude Quinn (MAR).