Barnes (pictured), who has been a regular between the sticks for the U's under-23s, will get the chance to experience first-team football, after joining the Wings for a month.
He will be straight into their squad for the game against Chelmsford City tonight, as Welling look to bounce back from a weekend defeat against Truro City.
The 21-year-old, who started out at Barnet and Fulham and joined Colchester via Bedford Town, has played twice for the U's first-team so far, against Brighton & Hove Albion in the League Cup and Charlton Athletic in the Checkatrade Trophy.
The Wings have also registered 19-year-old midfielder Cole Brown.
Brown made his debut for Hayes & Yeading United as 16-year-old.