Highlanders boss Terry Butcher has confirmed his 11th summer signing after tying up the 27-year-old defender on a one-year deal.
"Carl has been showing his paces with us and we've liked what we've seen", Butcher told the club's official website.
"He's very solid and an excellent tackler and I'm very pleased he's accepted a contract offer. He gives us another good option in defence where we have more strength in depth than at any time since I came here."
Left-back Tremarco joins from Macclesfield after spending last season on loan at Maltese side Floriana.