Prop Sam Lockwood will join Newcastle from Championship side Jersey at the end of the 2015-16 season.
The 27-year-old joined the islanders in January 2014 from Leeds Carnegie on loan before making a permanent move to St Peter later that year.
He has made 50 appearances for the island side and scored five tries.
He will not play for Jersey again after breaking his arm in the British and Irish Cup semi-final against his former club last month.
"Sam has been recognised as the best scrummaging loose-head in the Championship," said Newcastle director of rugby Dean Richards.
"He is a good all-round player who will benefit from the challenge of stepping up to the Premiership."
The former England Students player has agreed a deal at Kingston Park for the duration of next season.
"Sam has developed into a stand-out player in the Championship and it's not surprising that his performances have attracted the attention of a Premiership club," said Jersey head coach Harvey Biljon.
"He's made a fantastic contribution during his time in Jersey and we wish him all the best for the future."