The two players boast 149 Welsh caps and five Lions Tests between them and link up with the London side after leaving the Crusaders and Scarlets respectively.
The 35-year-old Halfpenny has headed home after spending time in New Zealand playing with the Crusaders and will be adding the English Premiership to the Super Rugby Pacifica, Top 14 and URC tournaments in which he had played in the past.
“Leigh’s experience speaks for itself, and he will bring plenty of leadership, expertise and high standards to our squad,” said Quins head coach Danny Wilson.
“He will also help to mentor our talented stable of back three players alongside bringing the benefit of his enormous experience to the wider squad. He’s an incredible athlete, highly skilful and adaptive across multiple positions, and we’re confident he’ll make a strong impact this season.”
Halfpenny has joined last season’s Investec Champions Cup semi-finalists with immediate effect as injury cover for the season. Wing Cadan Murley is a long-term absentee with a hamstring problem.
With 801 Test points in a Wales shirt and 49 for the Lions, Halfpenny earned a Grand Slam with Wales in 2012, a Six Nations title a year later and was part of the side that reached the semi-finals of the 2011 World Cup. He also went on three Lions tour, being named Player of the Series in Australia in 2013.
Joining him in the Grand Slam side and in the victorious 2013 Lions squad was Quins scrum coach Adam Jones. He has also played with Joe Marler on the 2017 Lions tour in New Zealand.
The English club already have two Welsh caps in their ranks in tight head prop Dillon Lewis and outside half Jarrod Evans, and have Wales U20 lock Johnny Green coming through their academy ranks.
“I’m grateful to Quins for the opportunity to continue my career at such an iconic club. I’ve always admired the Premiership and I’m keen to grab this opportunity with both hands,” said Halfpenny.
Loose head prop Jones, 32, left Scarlets after a decade of service at the end of last season and, like Halfpenny, will provide front row injury cover for the Quins. He made his Wales debut against Tonga in 2017 and was a Grand Slam winner and World Cup semi-finalist in 2019 and a Six Nations title winner two years later.
He toured South Africa with the Lions in 2021, forcing his way into the Test side for the third game against the world champion Springboks.
Having launched the career playing for Llandovery in the Welsh Premiership, he went on to make 136 appearances with the Scarlets, including helping them to win the PRO12 title in 2017.
“I can’t wait to test myself in the Premiership. I’ve heard great things about the club and their supporters, and I’m excited to work with Adam Jones to improve my game,” said Jones.
