The pair, both aged 24, will take over from Gary Ablett, who has spent six seasons in the role.
They have some experience in the role, sharing the captaining responsibilities for the last seven games of 2016 due to Ablett’s shoulder injury.
“We have spent a lot of time over the last couple of years identifying and developing our next generation of leaders,” coach Rodney Eade said.
“Steven and Tom have stood out throughout that process and their appointment as captains is recognition of their commitment to leading the future direction of the Gold Coast SUNS.
“Both guys have demonstrated they have the capabilities to lead and drive the team. And when Gary injured his shoulder last season we believed they were ready to take the next step and together they took the group to another level.
“That period of time was not only a defining period for them individually, but also the team and it became obvious then, that a co-captaincy model was right for us.
“It’s certainly an exciting period for the club, and we will have a fresh new look heading into 2017 – from new captains to nine new players and a new $22 million training and administration base now just weeks away from opening.”
Lynch and May, who were both foundation members of the club, have played 102 and 88 AFL games respectively.
The remainder of the leadership group will be finalised prior to the start of the JLT Community Series.