The team fielded well and Wairarapa U12 had some speed wobbles at 68-4, before getting through to their set total.
Coach Drew Morrison, a former representative player, said he was pleased overall.
"They are a fantastic group to work with, good skill sets that can be built on over the years.
"Our immediate focus will be to improve the fielding standards and teach the young lads how to anticipate the ball coming to them when fielding.
"This was a good solid first up run against older opposition."
The Under 12s had a thriller with Wairarapa U13, who reached their 163-9 target with the first ball of the 35th and final over, with just one wicket in hand themselves.
Batting first, Wanganui's Sam Sheriff made a watchful 39 off 83 balls, while Joel Clark (37 off 32) and Keightly Watson (23 off 25) picked up the pace.
Clark completed a good day with figures of 3-15 off seven overs, while Levi Woolston also did well with 3-26 off his maximum seven.
Henry Deans got three dismissals but Wairarapa's final pair survived to beat the Jason Clark-coached team.
Playing a full 50-over match, Wanganui U15 reached their 241 target with a strong batting effort to reach 242-5 after 41 overs.
Wanganui's Jack Mclead had grabbed 3-32 off seven overs, while Sam Beard was hard to get away, conceeding 28 from his full 10.
James Pennyfather with 2-50 off nine overs and Adam Bolt with 1-36 off eight also picked up scalps.
Coach Hayden Pudney was delighted with their run chase.
"Nick O'Leary and Mathew Simes got us off to a great start.
"Simes kept attacking but could not capitalise and departed for 18, O'Leary steadied the ship with 31 putting on a 69 partnership with Adam Bolt," Pudney said.
"Sam Beard made quick fire 47 before being run out.
"Josh Lennox, displaying some quality shots square of the wicket was the batting star with a solid 54 not out that saw Wanganui across the line." Lennox was later named man of the match.