Kevin Doyle broke the deadlock with a header in the 20th minute from Robbie Brady’s cross, but the result was not put beyond doubt until Alex Pearce struck a second with nine minutes remaining.
Martin O’Neill’s men now go on to play their first competitive game under their new manager when they travel to Georgia on Sunday.
The Omanis represented modest opposition and Ireland might have won more comfortably on a night when they hit the woodwork twice in front of a crowd of just 14,376 at the Aviva Stadium.
Quite what O'Neill will have learned from a game in which he rested most of his key men is a matter for debate, but there were positives other than the final score.
Everton midfielder Darron Gibson got 70 minutes under his belt in his first appearance since rupturing his anterior cruciate ligament on international duty in October last year, while veteran goalkeeper Shay Given played the first half on his return to the Ireland fold.
Given was largely a spectator as Oman failed to make anything of the handful of openings they created, while an understandably rusty Gibson got minutes under his belt and saw plenty of the ball at the base of O'Neill's midfield.
In a low-key start, Wes Hoolahan and Robbie Brady both had shots blocked at source and Mohammed Al Siyabi and Eid Al Farsi fired wide from long distance with Given only mildly concerned.
But the game came to life with 20 minutes gone when Doyle climbed highest to head Brady's inswinging corner past goalkeeper Ali Al Habsi.
From that point on, Ireland looked capable of adding to their tally with each attack, and midfielder Anthony Pilkington and Pearce both went close with the latter seeing his 32nd-minute header cleared off the line by Hassan Al Ghailani.
But it was David Meyler who went closest to a second goal before the break when Al Habsi could only divert Brady's left-wing cross into his path and the Hull midfielder, playing at right-back, controlled before chipping his effort delicately over the goalkeeper, only to see it come back off the post.
In the meantime, Al Farsi had wasted an opportunity to level when he scuffed his shot after being put through on goal, but Oman were able to muster little in the final third despite enjoying extended periods of possession.
Rob Elliot replaced Given at the break with the older man's work for the evening done, although the Newcastle man if anything found himself even more superfluous with Oman even less penetrative than they had been during the opening 45 minutes.
The Republic were little more threatening with Doyle's wayward 55th-minute header from a Pilkington cross a rare half-chance, although Al Habsi had to react sharply to prevent Pilkington from collecting Hoolahan's intelligent pass three minutes later.
O'Neill opted for chance as the hour mark approached, with Aiden McGeady, Robbie Keane and Shane Long replacing Pilkington, Hoolahan and Doyle.
Everton winger McGeady thought he had doubled Ireland's lead within seven minutes, only for defender Mohammed Al Musalami to hack his shot off the line.
Gibson was replaced by Glenn Whelan with 20 minutes remaining after being booked for an ugly challenge on Al Farsi which might have warranted sterner action in a competitive fixture.
Victory was assured with nine minutes remaining when Pearce stabbed home from close range, and both Keane and McGeady went close as time ran down, with the latter clipping the top of the bar with a curling 89th-minute effort.