The powerful 27-year-old will join from Worcester Warriors, subject to a medical and visas concluding the contract details.
Head coach Danny Wilson described his new recruit as “a really powerful carrier who can give us real go-forward with ball in hand”.
He added: “We’ve been looking to add to our options in the back-row, and he adds to the talent that we already have in that area. It’s another step forward in building depth in our squad.
“His recent form has been excellent for Worcester, including winning Man of the Match against Wasps, and we look forward to welcoming him to Scotstoun this summer.”
Earning 10 caps for his country since his international debut in 2017, he marked his first start the following year by picking off an interception and running 65 metres for a try against Wales in the Principality Stadium. His last cap came recently, against Romania in November last year.
At 6’1” Vailanu provides a powerful presence at the base of the scrum and having been regarded as a standout 7s player at Asahi University and impressing with Samurai RFC at the 2017 Hong Kong 10s. After catching the eye in Japan, he became a hit with fans of Saracens in a short spell there and then at Wasps before his move to Worcester. Now, remaining a Warrior but swapping cities, Vailanu is raring to go in Scotland this summer.
“I had multiple opportunities for next season in different countries but when the opportunity arose to join Glasgow, I didn’t think twice about it,” Vailanu told glasgowwarriors.org following the announcement.
“Glasgow has a rich tradition of success and with Danny [Wilson] as Head Coach and the players that we currently have, I have no doubts that tradition will continue next season and beyond.
“I cannot wait to get started and meet our fans at Scotstoun.”
The signing is the latest strengthening at Glasgow and Vailanu follows his countryman Walter Fifita to Scotstoun after he joined last October.