"He is a ball carrier and gives us a lineout option and we are delighted to have secured the services of a young international," said Turner, who replaced Chris Anderson in the Rodney Parade hot-seat last month.
The 26-year-old became only the second player to reach 50 Celtic League appearances with his previous club Glasgow but was surprisingly released in the close season. And Turner wasted no time in recruiting the Midlands-born lock when a deal to French side Narbonne fell through.
He said: "It was a stroke of luck he became available as he was due to join Narbonne but the move fell through."
Hall initially caught Turner's eye back in 1998 when he was at first club Moseley whom he left in 2001 to join Glasgow, grabbing 13 points in 104 appearances for the Scottish club. Although he has played mainly at lock, Turner intends to field Hall at No.6 after he impressed on a recent tour to Australia.
Hall qualifies for Scotland through his Falkirk-born paternal grandfather and won his only senior cap to date against the USA in San Francisco in 2002, after previously representing Scotland A, Scotland U21, Scottish Students and the Scottish Development squad.