After making his Wales debut in 2008, Halfpenny went on to become a great of European rugby, playing 101 times for his country and winning Six Nations Grand Slams in 2012 and 2019.
He played in three World Cups and also starred on the 2013 Lions tour of Australia, being named Player of the Series in a 2-1 series win.
Halfpenny’s move means he will play in the Premiership for the first time, having spent the majority of his career with Welsh sides Cardiff Rugby and Scarlets, plus three years in France at Toulon.
“I’m excited to join Quins and I’m grateful for the opportunity to continue my career with such an iconic club,” Halfpenny said.
“I have always admired the Premiership and I’m keen to grab this opportunity with both hands and contribute to the Quins DNA.”
