England collapsed to 66 for five chasing a modest 199 for victory. They were still in trouble in a match that was reduced to 45 overs per side due to a wet outfield when teenage debutant left-arm quick Josh Little took his fourth wicket.
England were now 101 for six against an Ireland side who have not qualified for the World Cup But wicket-keeper Foakes and Surrey team-mate Tom Curran (47 not out) saw England home with an unbroken stand of 98 as the visitors won with three overs to spare.
Victory in their opening match of the season saw England avoid the embarrassment of a fresh defeat by a side controversially excluded from an upcoming World Cup now reduced to 10 teams following their shock loss away to Scotland last year.
Things might have been different had Foakes, on 37, not survived a tight lbw appeal from veteran Ireland paceman Tim Murtagh. But Ireland opted against a review, with replays suggesting the ball may have gone on to hit leg stump.
James Vince and Dawid Malan, two of the batsmen looking to replace Vince in England's World Cup squad, opened the innings. When Vince (18) pulled Little to mid-wicket, England were 34 for one.
New batsman Joe Root was soon out for seven, the England Test captain falling lbw to Murtagh.
Little struck again when he dismissed Eoin Morgan for a duck after the Dublin-born England captain could only fend a brilliant bouncer behind to Gary Wilson.
Wicket-keeper Wilson, in his 100th match at this level, then held an even better catch—a diving one-handed grab high to his left—as Malan (24) slashed at Little.
David Willey helped staunch the flow of wickets before he holed out to long log off Little, who finished with fine figures of four for 45 Earlier, Liam Plunkett took four for 35 in an Ireland innings where paceman Jofra Archer marked his England debut with a wicket.
Barbados-born Archer, whose first ball in international cricket was hit for four by Paul Stirling, produced a 90.3mph yorker to bowl Mark Adair.
Ireland openers William Porterfield and Stirling put on 55 for the first wicket.
But when Archer held a diving catch at mid-on off Curran to dismiss Stirling for 33, it was the start of a slump that saw Ireland decline to 77 for four.