Officials in Canada or in the other country you are going to can ask you for documents to prove you can travel with your child. To avoid delays or being refused entry or exit at the border, it’s safest to have a travel consent letter signed by the other parent.
Even if you have sole custody, you may still be required to show that you have permission of your partner or anyone else that has access to your child, to travel with your child.
The only time you can travel freely with your child is if you have a parenting plan, separation agreement or court order that says you don’t need your partner’s permission to travel with your child. It’s important to carry a copy of your agreement or court order with you to prove that you don’t need anyone’s permission.