Paul Doolin's side will progress to the Elite Phase if they can avoid defeat against Scotland in their final fixture on Wednesday as Slovenia have already ensured their progress to the next phase following their 1-0 victory over the Scots this afternoon.
Leeds United striker Frankie Mulhern was a constant danger and got the opener in the ninth minute when he tapped the ball home from close range after a left wing cross by Graham Kelly was spilled by the Latvia keeper.
Latvia might have got back in the tie just two minutes later but their penalty appeals were waved away after Devids Dobrecovs was challenged by Robbie McCourt in the Irish penalty area.
In the 21st minute the dangerous Jason McClelland cut in from the right sent in a low left-footed strike which saw keeper Kristaps Zommers get down well to gather.
Mulhern just missed the target with a decent strike two minutes before the break and despite the wind and rain Ireland upped the pressure in the second half.
The second goal came in the 56th minute Graham Kelly steered the ball home after connecting with a right wing cross by Dylan Watts.
Mulhern threatened again in the 63rd minute when he drilled a low strike from the edge of the box towards goal but it whistles just wide of the Latvian upright.
Two minutes later Mulhern duly added the third goal when he raced onto a threaded pass from the impressive Connor Ronan to slot past keeper for a classy finish.
Six minutes from time Ireland had a let-off when Ričards Korzāns had a goal disallowed after appearing to handle the ball before finishing.
All in all the three points and three goals were well-deserved by Doolin's side and the Irish coached expressed his happiness afterwards.
"It was a very good performance and especially so considered the horrendous conditions," he said.
"We deserved to win against Slovenia on Friday when we were exceptional. Our play tonight again was very good. Latvia are a tricky enough side and against the breeze we defended well. They were getting balls into the box and looked to make it difficult for us.
"On Friday we got no luck considering the football we played but we deserved what we got this time around. Maybe we could have got one or two more and there were some great individual performances overall.
"It's our first clean sheet with this group and they're a good group of players who've been getting better and better each time. Scotland are a good side and reached the semi-finals of the European U17 Championships with this age-group in 2014 but we're going into that game in good form."
REPUBLIC OF IRELAND: Talbot, Deasy, McCourt, Elworthy, Sweeney, Poynton, Watts, Ronan, Mulhern (O'Connor 70), Kelly, McClelland.
LATVIA: Zommers, Sorokins, Džeriņš, Gulbis, Deružinskis (Grjaznovs 67), Jakovļevs, Juhnevičs, Zalaks, Dobrecovs, Tumanovs (Rubezis 52), Šilings (Korzāns 76)