Medicare Advantage

Medicare Advantage Open Enrollment: What Great Falls Can Change by March 31

GREAT FALLS, Mont. — If you signed up for a Medicare Advantage plan during the fall and now wish you'd chosen differently, you get a second look. The Medicare Advantage Open Enrollment Period runs January 1 through March 31, and it gives people already enrolled in an Advantage plan one chance to fix a mismatch before the year settles in.

This window is narrower than the fall Annual Enrollment Period, and the rules about what you can and cannot do surprise a lot of people. Here is what Great Falls residents should know before the March 31 deadline.

Who this enrollment window is actually for

The Medicare Advantage Open Enrollment Period, sometimes shortened to MA-OEP, is for people who are already in a Medicare Advantage plan as of January 1. If you are still on Original Medicare on that date, this window is not for you — you would need to wait for another enrollment period or qualify for a Special Enrollment Period.

That distinction matters. Every year, Great Falls residents call their local SHIP counselor in January hoping to jump from Original Medicare into an Advantage plan for the first time. Under current rules, that move belongs to the fall Annual Enrollment Period (October 15 – December 7), not this one.

What you can change between January 1 and March 31

If you are in a Medicare Advantage plan, here is what the rules allow:

• Switch from your current Medicare Advantage plan to a different Medicare Advantage plan.
• Drop your Medicare Advantage plan and go back to Original Medicare (Parts A and B).
• If you return to Original Medicare, you can also join a stand-alone Part D prescription drug plan.

You get one change during this window. Whatever you pick becomes effective the first day of the month after the plan gets your request. So a switch made in February takes effect March 1.

What you cannot do in this window

This is where mistakes happen. During the Medicare Advantage Open Enrollment Period, you cannot:

• Join a Medicare Advantage plan for the first time if you have only Original Medicare.
• Switch from one stand-alone Part D drug plan to another if you are on Original Medicare.
• Join a stand-alone Part D plan if you are already in an Advantage plan and staying in it.

If any of those describe your situation, you will likely need to wait for the fall Annual Enrollment Period or check whether you qualify for a Special Enrollment Period — for example, after a move, a loss of other coverage, or a change in Medicaid or Extra Help status.

The Great Falls picture

Great Falls is in Cascade County, where Medicare Advantage and Part D plan availability is set at the county level by the Centers for Medicare & Medicaid Services. If you want to see the specific plans offered in Cascade County, the Plan Finder at Medicare.gov lets you enter your ZIP code and your prescriptions to see what is available in your area.

Local help is free. Montana's State Health Insurance Assistance Program (SHIP) provides one-on-one counseling and does not sell insurance. That neutrality is valuable when you are weighing a change.

Common mistakes to avoid

A few pitfalls come up again and again:

• Dropping an Advantage plan without a Part D plan lined up. If you go back to Original Medicare and skip drug coverage, you could face a late enrollment penalty later.
• Assuming your doctors and pharmacies carry over. Networks and formularies differ from plan to plan. Confirm before you switch.
• Waiting until the last week of March. Paperwork can take a few days. Give yourself room.
• Confusing this window with the fall AEP. The changes allowed are different, and the effective dates are different.

Program facts worth knowing for 2027

Even if you do not make a change, a few numbers apply across Medicare:

• Part D out-of-pocket costs are capped at $2,100 in 2026 and $2,400 in 2027.
• The maximum Part D deductible is $615 in 2026 and $700 in 2027.
• The coverage gap — the old "donut hole" — was eliminated in 2025, so Part D now has three phases.
• The Medicare Prescription Payment Plan lets you spread your drug costs across the calendar year in monthly amounts instead of paying at the pharmacy counter.
• IRMAA income-related surcharges for Part B and Part D begin above $109,000 in income for a single filer in 2026.