Lake, who won her 50th Wales cap against Spain at Cardiff Arms Park in the summer, left reigning English champions Gloucester-Hartpury at the end of last season.
She was part of the side that lifted back-to-back Premiership titles in England. But now the experienced international centre will line up for Gwalia Lightning in the new expanded home and away Celtic Challenge tournament.
Lake made her Wales debut against Scotland in 2011 and is a widely respected and popular member of the national set-up. She has been a Wales regular and played in WXV1 and WXV2.
Brython Thunder and Gwalia Lightning will represent Wales in the cross-border competition between Welsh, Irish and Scottish teams.
The Lightning kick-off their campaign with a mouthwatering festive Welsh derby against the Thunder at Ystrad Mynach, on Saturday, December 21st (KO: 2.30pm).
Lake, said: “The chance to return home to Wales and to be close to my family was too good to turn down. Having spent most of my recent career playing in England, the opportunity to play back in Wales with a new team in a new competition is an exciting one.
“Like everyone I was an interested observer and watcher of Brython Thunder and Gwalia Lightning in their first season in the Celtic Challenge, I know Kate Williams had only good things to say about the Gwalia players, coaches and staff.
“It’s World Cup year and every player knows they have to play week-in, week-out, and having the chance to do that ahead of what promise to be the biggest year in the women’s game was another factor in my decision.
“The Celtic Challenge is a new tournament but has been a real launchpad for younger players to strive for Test honours with Wales, if I can help them and support them, it will only help Gwalia and ultimately national side.
Gwalia Lightning head coach Catrina Nicholas MacLaughlin, said: “To have someone of Kerin’s experience will be vital for what is a young and exciting Gwalia Lightning squad.
“The impact and experience that Welsh internationals Bryonie King and Kate Williams brought to the younger players was a big part of our success last season.
“Their leadership and ability to lead by example, on and off the field, allowed the likes of Catherine Richards, Gwennan Hopkins, Sian Jones and Molly Reardon to show what they could do and ultimately led to those players getting international recognition with Wales.
“If Kerin, with all her Test match experience with Wales, does the same then we will make significant strides this season. Her example could entice more international players to return home and we she will not be the last to play for Gwalia or in the Celtic Challenge.
