The 25-year old Breton was rumoured to be looking to leave Sunweb for a French team and it's now confirmed.
Barguil was no doubt able to negotiate more favourable terms after standing on the podium in Paris twice - in polka dots and for the most combative prize - and finishing 10th overall.
With an aggressive Tour de France itself, finishing eighth overall in the teams classification, Team Fortuneo-Oscaro is looking to build around Barguil as it hopes to step closer towards the WorldTour.
"It is with great pride for the team to see the arrival of a great champion like Warren," Team Fortuneo-Oscaro Emmanuel Herbert manager said in a team statement.
"He will be able to count on all the desire and collective strength of a team that has long been waiting to support a strong leader, capable of winning the biggest races at the international level."
Barguil said it was also important the team has 'Breton DNA'.
"I am very happy to join the Fortuneo-Oscaro team and I have watched the team's rise in recent years."
"Emmanuel understood how I wanted to work in the image of what I was able to do on the last Tour de France, to let my natural temperament of attacker speak and not change the things that worked well!"
The team is further bolstered by the signing of domestique Amaël Moinard after seven years at BMC.
"I was seduced by the sporting challenge proposed by Emmanuel Hubert and Warren Barguil," the Frenchman said. "And I know Warren well. I join a group that is already powerful and focused on the offensive. The goal will be to unite the team around Warren, a strong and charismatic leader."
While Sunweb may not be happy to see such an exciting prospect go, it does mean the team won't have to juggle two leaders at next year's Tour de France should the course suit 2017 Giro d'Italia champion Tom Dumoulin.
But it is likely to be a bit of a blow for Australian fans who'd come to know him as 'Wazza' during the Tour and watched the 'roomie' friendship of Michael Matthews and Barguil unfold.
Maybe reliving the bromance with this video might help soften it: