Anthony Foley made a rare appearance for Shannon as the Limerick men accounted for Blackrock College at Coonagh.
Munster favourite Foley came on as a second half replacement as the former champions maintained their 100% start to the league campaign.
Blackrock were only 10-7 behind at half-time as winger Shane Monahan (29 minutes) replied to a fifth-minute try from Shannon centre Joe Manuel.
But Shannon were far more clinical and tries from number 8 and captain David Quinlan and winger Stephen Kelly sealed the issue.
Shannon made it eight league wins on the trot - five of them coming since the start of the current season - with another Munster player, this time it was Foley, having a cameo.
A month ago it was Munster prop Marcus Horan who was assisting Mick Galwey's side.
Just like Horan, Foley, who incredibly played for Shannon against Blackrock back in January 1995, strengthened the Shannon scrum considerably on his introduction and had a decent run-out after sitting on the bench for Munster's loss to Leinster last night.
Blackrock, winners over Dungannon and Lansdowne recently, ventured south with a side full of youth and experience but they fell behind early on when Manuel, a replacement for John Clogan, blazed over after a turnover and a smashing 30-metre break by Andrew Finn.
Andrew Thompson converted and 'Rock missed two successive penalty chances after 7 and 9 minutes as usually reliable full-back Fionn Carr was off target.
The Dubliners got back on terms though when former Ireland Under-20 flyer Monahan skipped past two tacklers and jinked his way over for a lovely try which Carr converted.
A Thompson penalty, struck late in the half, was the difference between the sides at the interval but Shannon, bolstered by Foley's inclusion, took control in the second period.
Thompson knocked over his second penalty before Quinlan notched his try. Scrum half Fiach O'Loughlin helped set up the score by sending an excellent kick into the right corner. Shannon came up with lineout possession and Quinlan was quickly mauled over the whitewash.
Thompson landed another penalty in the 57th-minute but 'Rock had a decent spell of possession and territory in the final quarter and should have registered at least another try.
Shannon had taken their foot off the pedal but having soaked up that pressure, they launched an 80th-minute counter attack which led to the speedy Kelly cutting through for his try.
Shannon: Tries: Joe Manuel, David Quinlan, Stephen Kelly; Con: Andrew Thompson; Pens: Andrew Thompson 3
Blackrock College: Try: Shane Monahan; Con: Fionn Carr
Garryowen 8-19 Clontarf
Champions Garryowen slipped from fourth to seventh in the Division One table after Clontarf outplayed them at Dooradoyle.
'Tarf gained revenge for last season's semi-final defeat to Garryowen as Leinster prop Cian Healy and lock John Duffy helped themselves to tries.
Healy crossed in the second-minute to strike an early blow for the visitors who led 11-3 at half-time.
Duffy's try and Ian Keatley's third penalty of the afternoon left Garryowen trailing by 16 points before Munster winger Keith Earls grabbed a late try.
Garryowen have stuttered of late in the AIB League. This is their second defeat in four league games and next weekend's visit of Dungannon to Dooradoyle is a real must-win game for Dara Ryan's outfit.
The title holders are eight points off their arch rivals and current table-toppers Shannon.
After two recent defeats, Clontarf looked to be struggling but this success - the club's second consecutive league win at Dooradoyle after their victory there in January 2006 - has them back up in sixth place, three points off a play-off spot.
Garryowen played a part in their own downfall as a mistake by their out-half Alan Kingsley led to 'Tarf's opening try. The Dubliners pressed and put the rampaging Healy, who was used as a replacement against Munster last night, over for a sucker-punch try.
Ian Keatley, who, like Healy, was part of last season's Grand Slam-winning Ireland Under-20 team, missed the conversion but he added a seventh-minute penalty which Garryowen full-back Conor Kilroy soon cancelled out.
Kilroy's kick proved to be Garryowen's only points until Earls' late try as the heavier Clontarf pack managed to dominate up front and provide half-backs Keatley and Paul O'Donohoe with a solid platform of possession.
Keatley knocked over his second penalty for an 11-3 interval lead for the visitors and he repeated the trick early in the second half.
Then came one of the game's most pivotal moments when 'Tarf picked off a turnover near halfway and launched a thrilling counter attack towards the clubhouse end through O'Donohoe.
The ball was switched to winger Max Rantz-McDonald who made good yardage before lock John Duffy managed to barrel over from close range and put his side 19-3 in front.
Garryowen tried manfully to mount a comeback and brought on Declan Lavery, Frank McKenna and Anthony Kavanagh to try and make some difference up front.
The hosts did muster a late try when Kilroy spotted plenty of space on the blindside and his spiralled a kick into the air for Earls to catch to dot down. But with the conversion attempt sailing wide, any thoughts of a push for a losing bonus point quickly evaporated.
Garryowen: Try: Keith Earls; Pen: Conor Kilroy
Clontarf: Tries: Cian Healy, John Duffy; Pens: Ian Keatley 3
Dolphin 21-5 Lansdowne
Dolphin maintained their grip on third place in the Division One standings with this well-deserved victory over Lansdowne at Musgrave Park.
Despite the Lansdowne pack gaining parity in the first half, Dolphin still went in at the break 13-0 in front thanks to a 33rd-minute try from winger Rory Kenneally.
Two minutes into the second period, home prop Fergus Gately was driven over. Out-half Barry Keeshan kicked 11 points in total for Dolphin, while full-back Justin Meagher grabbed a late consolation try for Lansdowne.
Beaten by Blackrock College last time out, Lansdowne travelled looking for their first league win over Dolphin at Musgrave Park but David O'Mahony's home side have quickly become a force to be reckoned with.
With the division's top scorer Keeshan pulling the strings behind a powerful pack which includes Munster's James Coughlan, Dolphin are deservedly riding high in the table currently.
Their centre pairing of Eric Maloney and Duncan Richardson is a very solid one and the Corkmen like to mix it behind the scrum as well.
Today's clash was somewhat of a slow burner with Keeshan opening the scoring with a penalty in the 21st-minute. A defensive mix-up amongst the Lansdowne backs allowed Dolphin to capitalise and put flying right winger Kenneally over for a well-taken try.
Keeshan converted and things got even better for Dolphin when Lansdowne lost back rower Pom Simone to a yellow card for killing the ball. As the rain continued to fall in worsening conditions, Keeshan slammed over his second penalty for a 13-0 scoreline.
Just two minutes after the break, tighthead prop Gately was driven over for Dolphin's second try and while Keeshan missed the conversion, the former Cork Constitution player nabbed another penalty in the 56th-minute for 21-0.
Dolphin could have scuppered their chances when they had two players sin-binned in quick succession. The aforementioned Maloney (63 minutes) and Coughlan (73) both saw yellow but Dolphin's defence held out until Meagher crossed the whitewash two minutes from time.
Scorers: DOLPHIN: Tries: Rory Kenneally, Fergus Gately; Con: Barry Keeshan; Pens: Barry Keeshan 3
LANSDOWNE: Try: Justin Meagher
Galwegians 0-18 UL Bohemians
Paul Warwick made a try-scoring debut for UL Bohemians as they brushed aside Galwegians at Crowley Park.
The Munster out-half, who was a second half replacement, created a try for centre Mark Butler and scored one of his own.
Having played against a strong wind in the first half, Bohs were effectively in the driving seat as the sides turned around at 0-0.
Warwick and Colman Finn combined for Butler's try and a Lupeni Siale pass put Warwick over for his clinching score.
Galwegians suffered their third league defeat on the trot as they fell from eighth to eleventh in the table, while Bohs' victory - their fourth in sixth league meetings with the men from the west - moved them up one place from fifth to fourth.
'Wegians, who included Connacht's Alipate Tuilevuka and Peter Durcan, had the backing of a strong wind in the first half, but Bohs literally weathered the storm and anything the hosts could throw at them.
The second half was five minutes old when Bohs out-half Fergal Lawlor opened the scoring with a neat penalty kick.
The Limerick men, captained by former 'Wegians winger Martin McPhail this season, seemed to grow in confidence after that, particularly with the inventive Warwick making their plays.
Lawlor was replaced by Warwick and the Australian had an almost immediate impact as his lovely skip pass put centre Finn into space. Bohs' former skipper made good ground before offloading for Butler to tear away and make the line.
Warwick missed the conversion in tricky conditions but he soon added a penalty and with 'Wegians failing to muster anything in attack, the points were sealed when winger Siale lobbed a pass out for Warwick to dash over for a try which he converted himself.
UL Bohemians: Tries: Mark Butler, Paul Warwick; Con: Paul Warwick; Pens: Fergal Lawlor, Paul Warwick