England U20 star joins Sharks
The 19-year-old was at London Irish last season where he progressed through their academy, but he failed to make a first-team appearance for the club.
He had agreed to join National League One side Darlington Mowden Park this summer but has now agreed to a long-term deal with the Sharks.
"I definitely see this as a chance to play first-team rugby," Langdon said.
"There aren't too many hookers here so I hope there will be opportunities to play for the first team and then I hope to kick on.
"It's been really good so far, it's a great bunch of lads, and the facilities are really good.
"It's a great coaching set up and I'm just excited for the future here.
"The opportunity arose to come here, and it seemed the best decision for me, with the new owners coming in at Sharks, it's a real club that's going forward," he added.
