An estimated 46,000 Sunderland fans made their way to England's national stadium, and a goal from Elliott Embleton in in the first half and Ross Stewart in the second ensured they'd make the long trip from London back to the north east in buoyant mood.
Alex Neil's side entered the match on the back of a 15-game unbeaten run, which had propelled it into the play-off spots, and the Black Cats settled into a groove early, Embleton scoring in the 12th minute with a long-range drive that bemused a flailing David Stockdale in the Wycombe goal.
Chances were few as the half developed, but Sunderland always looked the more comfortable, and its place in the Championship was confirmed when Stewart netted his goal with a precise finish with little more than 10 minutes of the contest remaining.
Jack Clarke had a chance to add further gloss to the scoreline but was denied by Stockdale at close quarters, but it mattered little as Sunderland's faithful exploded into rapturous celebrations upon the final whistle.
Sunderland will join the automatically promoted duo of Wigan Athletic and Rotherham United in the Championship next season.