Hardy has been competing with fellow Wales scrum-half Reuben Morgan-Williams for the Ospreys’ number nine jersey, while Luke Davies and Harri Morgan are also on the books.
“Kieran is a vital asset to our squad, so we’re delighted he has signed a new deal,” said Ospreys head coach Mark Jones.
“His contributions both on and off the field in have been invaluable for us.
“We’re blessed with an extremely talented scrum-half group, who all bring different attributes to the table.
“Each of them share the key characteristics and traits we look for in an Osprey.”
Ospreys’ future as a professional side has only been guaranteed until June 2027 amid the Welsh Rugby Union (WRU) controversial plans to cut a men’s professional team.
Swansea-based Ospreys and Scarlets are expected to compete for a single west Wales licence.
