My babies mother moved out of state with our kids and I did not give her consent to take our children. What can I do in order to get my kids back?

I am sure we don't know everything about your situation, can you tell us more? S there any legal agreement or court order between the two of you?

What state are you at, where did they move ?

Is there a child custody order in place, does she have custody? Do you have court ordered visits ? Have you been visiting.
How long ago was this that she moved ?

Get a lawyer.

Without knowing what states are involved, whether there were any court orders involving custody and visitation, whether you are the legal father, what the ages of the children are, how long ago did they move and maybe more, we can't help.

How long ago was all this?

No there is no court order or legal agreement. She told me she was going to visit her mom in Hawaii and she hasn't came back. Its been 7 months. I live in California. I have sent her money numerous times and I even bought their tickets for them to come back. She won't bring them back. Before she left with my kids, they were living in my house and I was their sole provider

We asked several questions, we need the answers to all of them and maybe more to help.

But based on your last response, your only recourse (and at 7 months it may be too late) is to file in your CA courts for custody of the children. And hope the court awards you custody. In that case, you can travel to HI and retrieve the children.

We asked several questions, we need the answers to all of them and maybe more to help.

But based on your last response, your only recourse (and at 7 months it may be too late) is to file in your CA courts for custody of the children. And hope the court awards you custody. In that case, you can travel to HI and retrieve the children.

Yes-it is too late. The OP must file in Hawaii.
According to UCCJEA
The state which is currently the "home state" of the child, or was the child's home state within six months immediately before the commencement of child custody proceedings if the child is absent from the state, but a parent or person acting as a parent continues to live in the state;

Its close enough top give it a shot. Did the mother establish residency immediately upon arriving. That is a question that I think a court has to rule on. Ostensibly she was there for a visit. Did she visit with family and then get her own place after a month or so? These are fine points that could mitigate the amount of time counted towards establishing the children's home state.

The OP should consult a local attorney who can advise better on these points.