When parents and children live in different states, California cannot decide custody merely because one parent files here first. Interstate custody jurisdiction is governed by the Uniform Child Custody Jurisdiction and Enforcement Act, which determines which state has authority to make or modify custody and visitation orders.

The rules are designed to discourage competing cases, promote cooperation between courts, and keep custody decisions in the state with the strongest lawful connection to the child.

The Child’s Home State Usually Has Priority

For an initial custody determination, the child’s home state is ordinarily the state where the child lived with a parent or person acting as a parent for at least six consecutive months immediately before the case began. For a child younger than six months, the home state is generally where the child lived from birth.

Temporary absences usually count as part of the six-month period. California may also retain home-state priority for a limited period after a child leaves if California was the home state within six months before filing and a parent or person acting as a parent continues living here.

Physical presence in California does not, by itself, establish ordinary custody jurisdiction.

Other Jurisdictional Bases May Apply

If no state qualifies as the home state, or the home state declines jurisdiction because California is more appropriate, California may act when the child and at least one parent have a significant connection here and substantial evidence concerning the child’s care and relationships is available here.

California may also act when every other state with potential jurisdiction declines or when no other state qualifies under the governing standards. Parents cannot create custody jurisdiction simply by agreeing that California should decide the case.

Existing Orders Change the Analysis

When another state has already issued a custody order, that state may retain exclusive authority to modify it. A California court must review the prior proceeding and may need to communicate with the other court.

Except in an emergency, California generally cannot move forward with a competing custody case when a proceeding is already pending in another state exercising jurisdiction consistently with the governing law.

Temporary emergency jurisdiction may be available when a child is present in California and immediate protection is necessary because of abandonment, mistreatment, or abuse. Emergency authority does not automatically become permanent authority.

Address Jurisdiction Before Litigating Custody

Parents should disclose the child’s addresses, caregivers, prior custody cases, and existing orders accurately. Travel records, school files, leases, and medical records may help establish where the child lived and whether an absence was temporary.

A California child custody attorney can analyze home-state status, coordinate registration or enforcement of an existing order, and address interstate court communication before the parties spend resources litigating in a state that may lack authority to decide the dispute.