After confirming his departure for the Scarlets, Davies said he was looking for one more opportunity in club rugby.
Davies played junior club rugby for St Clears and Whitland before joining the Scarlets academy.
The center has captained Wales on four occasions and played in six Tests over two tours with the British and Irish Lions in Australia and New Zealand in 2013, winning the Man of the Series award against the All Blacks.
In addition to playing in two World Cups with Wales, Davies, nicknamed Foxy, went on to win two Grand Slams and two Six Nations Championship titles.
The centre, who spent two years with French side Clermont Auvergne, helped the Scarlets win the Pro12 title in 2016-17.
“I have so many people to thank: my dedicated and loyal fans, great teammates, supportive coaches, staff, friends, and most of all, my family for believing in me,” Davis added on Instagram.
“Thank you so much for your support, especially when I have faced challenges and setbacks due to injuries. It has been an incredible journey, with two Lions Tours, two Grand Slams and a Pro 12 title.
“I was fortunate enough to play professionally for 18 years and give everything I had to become the best rugby player I could be.
“I now look forward to what the next 18 years will bring – as a father, as a husband, and in my next career chapter. Diorci, Foxy.”
