The parent that the child lives the most months with throughout the year is the one who can claim them. You would have to show proof of where the child lives to be able to claim them. My ex lives 1000 miles away from me and claimed the kids.. They live 100% of the time with me. He had already gotten his return back when I filed. I had to show school records when I filed my taxes. I got my refund and he had to pay his back. He tried to say that they lived with him, but since he couldn't show proof, I got to claim them. The only way the non custodial parent can claim the kids on their taxes is if the custodial parent allows them to and doesn't claim them on their taxes.