Shannon have never been outside the top tier in the league and they launched their comeback in this season's campaign with a deserved win over UL Bohemian at Thomond Park.
They remain bottom, but this first win of the season will be a terrific boost for their remaining 10 games, seven of which will be in Limerick.
UL Bohemian opened the scoring with a try from former Munster and Shannon player Mossie Lawler. He won the race for the touchdown following a grubber kick by out-half JJ Hanrahan after 14 minutes.
Tadhg Bennett had Shannon's first points when he landed a penalty from 30 metres after 23 minutes and he had a second three minutes before the interval after Ian Condell was sin-binned for persistent offside.
Within a minute of the restart UL Bohemian got back in front when Hanrahan landed a penalty.
In the game's best move, Shannon opened up the home side's defence and replacement John Sheerin crossed for a try that Bennett converted.
Hanrahan missed a penalty chance for UL Bohemian and late on Rob Guerin hit another Shannon penalty.
Shannon remain bottom of the table, four points behind last night's losers.
UL Bohemian – B Martin; A Rossiter, M Lawler, N Kenneally, R Whyte; JJ Hanrahan, C Sheridan; T Burke, E Rossiter, G Walsh; E Kelly, D Frawley; C Kindrigen, I Condell, S Rennisson. Replacements: J Sutton, G Lenehan, J O'Donoughue, B Walsh, D Fitzgerald.
Shannon – J Loxton; M Darcy, E Moloney, R Mullane, D Donovan; T Bennett, R Guerin;J Cronin, D Casey, G McNamara; S McCarthy, M Culhane; E McLoughlin, J Murphy, M Essex. Replacements: M Corby, G Brithfield, J Shine, J Sheerin, W O'Connor.
Ref – P Fitzgibbon (IRFU).