The England pair, ranked 25th in the world and seeded third in the capital, looked like having it all to do to reach the mixed doubles showpiece as they went up against favourites Danny Bawa Chrisnanta and Yu Yan Vanessa Neo from Singapore in their semi-final.
But Langridge and Olver needed just 41 minutes to secure the win, beating their opponents 21-15 21-15.
The English National champions will now take on German second seeds Michael Fuchs and Birgit Michels for the title.
"We are really pleased," said Langridge. "We knew before the game it was going to be tough.
"At the beginning of the year our opponents were in the world's top ten but we played well against them.
"We spoke to our coaches and they gave us a really good plan. To be honest the plan they gave us worked down to a T."
Olver added: "It's great walking out to a roaring crowd. At the start of the game we were a bit nervous but when you know everybody wants you to win, wanting you to play well, it helps a lot."