How to modify child custody and parenting time in Montana
Sources last checked 7 November 2026. Information only, not legal advice. This page rests on the text of Montana Code Annotated 40-4-219 (amendment of a parenting plan), 2025 edition, as published on mca.legmt.gov. Montana calls custody arrangements a “parenting plan”. Read what we could not confirm below.
The short version
Montana’s statute states the test directly. Under MCA 40-4-219(1) the court “may in its discretion amend a prior parenting plan” if it finds, based on facts that arose since the prior plan or were unknown to the court then, that “a change has occurred in the circumstances of the child” and that the amendment is “necessary to serve the best interest of the child”. So you need both a change and a best-interest reason. For support instead, see modifying child support and spousal support in Montana.
What the court considers
- Impact on the child. The court considers the potential effect of the change on the best-interest criteria in MCA 40-4-212 and whether the parents agree, the child was integrated into the petitioner’s family with parental consent, the child is 14 or older and wants the change, or one parent has willfully and consistently blocked the other parent’s contact.
- Blocking contact. The court “shall presume a parent is not acting in the child’s best interest” if that parent willfully and consistently refuses or frustrates the other parent’s contact with the child (subsection 3).
- Moves. If a parent has changed or plans to change the child’s residence in a way that significantly affects the other parent’s contact, the court also weighs whether visitation can preserve the relationship, each parent’s reasons for or against the move, whether the moving parent will promote the other parent’s relationship, and reasonable alternatives to the move. It may set a new schedule and divide transportation costs.
- De facto arrangements. A court may modify a de facto parenting arrangement using the MCA 40-4-212 factors.
Filing rules in the statute
- Proposed plan. A proposed amended parenting plan “must be filed and served with the motion for amendment” and with the response. The statute also says preference must be given to carrying out the existing plan.
- Repeated or frivolous filings. Attorney fees and costs “must be assessed” against a party whose amendment action is vexatious and amounts to harassment.
- Serious criminal convictions. If a parent or someone in that parent’s household has been convicted of a listed crime, such as homicide, sexual assault, child sex trafficking or strangulation of a partner or family member, the other parent may file an objection. The parent served has 21 days to respond or parenting rights are suspended until further order. If that parent objects, a hearing must be held within 30 days of the response.
- Dispute resolution. Except in cases of abuse or threats of abuse or a listed conviction, the court may order counseling, mediation or other dispute resolution.
- Military service. A modification based on military service orders is temporary and reverts to the previous plan when service ends, and the parent’s absence for service cannot be considered when a later motion is decided.
- Death of a parent. A plan may be amended under MCA 40-4-221 on the death of one parent.
Forms and filing
We did not locate a Montana court form for amending a parenting plan. The court that entered your decree normally keeps the case, so ask that court’s clerk about forms, fees and local rules. See child custody in Montana for the broader picture.
What we could not confirm
- Case law. We read only the statute. We did not read Montana Supreme Court opinions on what counts as a change in circumstances, so we cannot say how strictly courts apply it or how they treat a move.
- Time limits. We did not check whether other statutes limit how soon after a decree you may file.
- Best-interest factors. We did not read the text of MCA 40-4-212, which the amendment statute cross-refers to.
- Procedure. We did not read the jurisdiction act (UCCJEA), temporary orders, filing fees, fee waivers or local rules.
Sources
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