The central defender, 27, has recent European experience from his time with the Lakesiders, featuring in their recent Europa Conference League first qualifying round tie against Sligo Rovers.
He previously played for a number of other Welsh clubs, including Connah’s Quay Nomads, Aberystwyth Town, and Airbus UK.
Following the recent captures of striker Jake Burton and midfielder Jordan Lussey, Spittle arrives at Rossett Park as the Mariners prepare for their return to the Pitching In NPL Premier Division.
The Mariners visit Guiseley on the opening day of the season next Saturday.
“Jonny has lots of experience and has been coveted by a number of clubs in the English system," manager Neil Young said.
“He is an accomplished defender who has a great attitude, and in the talks to bring him here it was clearly evident that he wants to come to Marine and make a difference.”
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