Prescription Coverage in Montana: A 2027 Medicare Part D Guide

Drug coverage under Medicare got a major overhaul for 2027. This guide covers the $2,400 out-of-pocket cap, how the coverage phases work, and what people in Montana should know — no jargon, no sales pitch.

One fact shapes every Medicare decision in Montana: your county, not your state, sets your options. Neighboring counties can look surprisingly different, which is exactly why the guides here are local.

About 30% across Montana have chosen Medicare Advantage over Original Medicare, though that share swings a lot depending on where you live.

Ahead: the companies active statewide, how Original Medicare, Advantage, Medigap and Part D fit together, the shared 2027 costs, enrollment windows, free unbiased help, and a guide for every Montana city.

Part D, phase by phase

Part D is Medicare's prescription-drug coverage, and you can get it either on its own alongside Original Medicare or baked into a Medicare Advantage plan. The government sets the structure; private insurers run the plans.

Here's the shape of a 2027 plan: you first pay a deductible (capped at $700), then share costs during initial coverage, and finally hit a catastrophic phase where a new yearly out-of-pocket cap kicks in — the old coverage gap has been eliminated. If lumpy pharmacy bills are a worry, the Medicare Prescription Payment Plan can spread them monthly.

We explain how all of that plays out in Montana. Because each plan's drug list and pricing differ, the plan-specific details belong on Medicare's Plan Finder — we don't rank plans.

The 2027 numbers, from shared to plan-specific

Start with what's fixed for everyone. The standard Part B premium is $202.90 per month in 2026 (2026 amount; 2027 figure will be posted when CMS releases it), and Part A is premium-free for most people who paid Medicare taxes long enough while working.

On the drug side, Part D has real guardrails for 2027: a deductible capped at $700 and, a hard $2,400 ceiling on your out-of-pocket costs for covered prescriptions — the old coverage gap is gone.

Higher earners pay more for Parts B and D through an income-related adjustment called IRMAA, which for 2026 starts above $109,000 in annual income for an individual and is based on your 2024 tax return. Most people fall below that line and pay the standard amounts. The 2027 brackets will be posted when CMS releases them.

Everything past that is plan-specific: the premiums, copays, and coverage details of an individual Advantage or Medigap plan change from plan to plan and year to year. Rather than quote or rank those, we point you to Medicare's Plan Finder and a licensed agent for your exact numbers.

When you can enroll or make changes

Medicare's enrollment windows are federal — the same nationwide — so the timing below applies wherever you live.

Your first window (IEP). When you're new to Medicare, your Initial Enrollment Period is the 7-month window around your 65th birthday month. Signing up on time helps you avoid late penalties that can follow you for years.

Annual Enrollment Period (AEP). Each fall, from October 15 – December 7, anyone with Medicare can join, switch, or drop a Medicare Advantage or Part D plan. Changes take effect January 1.

Medicare Advantage Open Enrollment. From January 1 – March 31, if you're already in an Advantage plan you get one chance to switch plans or return to Original Medicare.

Special Enrollment Periods can also open after certain life events, like moving or losing other coverage. The interactive calendar further down lays the year out visually.

Getting unbiased help in Montana

You never have to make these decisions alone, and you don't have to pay for good help. A few free, trustworthy starting points:

Medicare.gov and 1-800-MEDICARE (TTY 1-877-486-2048) are the official sources for plan details and the Plan Finder. Licensed agents can also compare options with you and handle enrollment.

And to be clear about who we are: MyMedicarePlans.org is a privately owned, independent educational resource. We are not Medicare, not a government agency, and not affiliated with one. We publish plain-language information to help you get oriented — then point you to the official sources and licensed professionals for decisions about specific plans.

Montana cities

Pick your city for the county-level picture, the companies active in your area, and local guides: