Best Medicare Supplement Plans in Montana 2026
Montana has over 185,000+ Medigap enrollees. Plan G starts at $129/mo in Billings and averages $237/mo statewide. We compared 30+ carriers to find the best coverage in Big Sky Country.
Montana Has No Birthday Rule: Your Initial Plan Choice Matters
Unlike California, Oregon, and other states with birthday rules, Montana does not give you an annual window to switch Medigap carriers without underwriting. Once your 6-month Open Enrollment Period ends, you will face health questions if you try to change plans. Compare carriers carefully before you enroll and consider long-term rate stability, not just today's lowest premium.
More than 185,000 Montanans have Medicare Supplement Insurance, also called Medigap. Montana follows standard federal Medigap rules, offering plans A through N with no state-specific modifications. Plan G is the most popular choice for new enrollees, covering nearly all Medicare out-of-pocket costs except the annual Part B deductible ($283 in 2026).
Montana does not have a birthday rule or anniversary rule, which means your 6-month Open Enrollment Period when you first turn 65 and enroll in Part B is your best and most important opportunity to lock in coverage. After that window closes, carriers can use medical underwriting to deny your application or charge higher premiums based on your health history.
Plan G premiums in Billings range from $129/mo (WMI Mutual) to $231/mo (Cigna) for a 65-year-old. WMI Mutual is the clear price leader at 46% below the state average. For seniors who want all 10 plan types with issue-age pricing, Transamerica at $156/mo is the top pick. State Farm stands out with an A++ AM Best rating and local agents across Billings, Missoula, Great Falls, and Bozeman.
Best Medicare Supplement Companies in Montana
Ranked by MedicareFAQ Score, which weighs financial strength, customer satisfaction, premium competitiveness, plan availability, and discounts.
WMI Mutual
Plan G
$129/mo
Plan N
$107/mo
AM Best
A-
WMI Mutual offers the lowest Plan G and Plan N rates in Montana for 2026. Plan G at $129/mo is 46% below the state average of $237/mo, making it the best value for Montana seniors who want comprehensive coverage at the lowest possible cost. WMI also offers the lowest Plan A in Montana at $96/mo.
Transamerica
Plan G
$156/mo
Plan N
$127/mo
AM Best
A
Transamerica is the only Montana carrier offering all 10 standard Medigap plan types with issue-age pricing. Their Plan G at $156/mo is competitive, and they offer the lowest Plans D, K, and L in Montana. Issue-age pricing means your rate is locked at the age you enroll, which can save money over a 10 to 20 year horizon.
Nassau
Plan G
$159/mo
Plan N
$122/mo
AM Best
A-
Nassau offers the lowest Plan F rate in Montana at $192/mo and competitive Plan G and Plan N pricing. Plan F covers the Part B deductible that Plan G does not, making it relevant for those who enrolled in Medicare before January 1, 2020.
Mutual of Omaha
Plan G
$179/mo
Plan N
$N/A/mo
AM Best
A+
Mutual of Omaha is the most trusted Medigap brand in Montana, combining an A+ AM Best rating with the lowest Plan C rates in the state at $182/mo. Their High-Deductible Plan G is also available for seniors who want the lowest possible monthly premium with a deductible safety net.
State Farm
Plan G
$195/mo
Plan N
$N/A/mo
AM Best
A++
State Farm holds the highest possible AM Best rating (A++) and offers local agents across Billings, Missoula, Great Falls, and Bozeman. For Montana seniors who prefer face-to-face service and want the highest financial strength rating, State Farm is the top choice.
Medicare Supplement Prices in Montana
Sample monthly premiums from top carriers in Billings for a 65-year-old female nonsmoker. Rates may include available household discounts. Montana uses attained-age rating for most carriers, so premiums will increase as you age.
| Insurance Company | Plan G Monthly | Plan N Monthly | Plan F Monthly |
|---|---|---|---|
| WMI Mutual | $129 | $107 | N/A |
| Transamerica | $156 | $127 | N/A |
| Nassau | $159 | $122 | $192 |
| Mutual of Omaha | $179 | N/A | $215 |
| State Farm | $195 | N/A | N/A |
| AARP / UnitedHealthcare | $218 | $165 | $248 |
| Humana | $224 | $171 | $252 |
| Cigna | $231 | $178 | $259 |
Source: Montana CSI, FairSquare Medicare, MoneyGeek, May 2026. Rates vary by ZIP code and age. N/A indicates plan not offered by that carrier.
Plan G vs. Plan N in Montana
Plan G and Plan N are the two most popular Medicare Supplement plans for new enrollees in Montana. Here is how they compare.
| Coverage Feature | Plan G | Plan N |
|---|---|---|
| Part A hospital coinsurance | Covered | Covered |
| Part B coinsurance (20%) | Covered | Covered* |
| Part A deductible ($1,736) | Covered | Covered |
| Part B deductible ($283) | Not covered | Not covered |
| Part B excess charges | Covered | Not covered |
| Skilled nursing coinsurance | Covered | Covered |
| Foreign travel emergency | Covered | Covered |
| Office visit copay | $0 | Up to $20 |
| ER copay (no admission) | $0 | Up to $50 |
| Avg. monthly premium (Billings) | $129-$179 | $107-$127 |
*Plan N covers Part B coinsurance but may charge up to $20 for some office visits and up to $50 for ER visits that do not result in inpatient admission. Montana allows excess charges, so Plan N enrollees should confirm their doctors accept Medicare assignment.
Montana has no birthday rule, so your initial enrollment decision is the most important one you will make. WMI Mutual at $129/mo is the clear price leader, but it only offers Plans A, G, and N. If you want all 10 plan types or issue-age pricing that locks your rate at enrollment, Transamerica at $156/mo is the better long-term choice. For the highest financial strength rating (A++) with local agents in Billings, Missoula, Great Falls, and Bozeman, State Farm at $195/mo is the top pick. Do not just chase the lowest premium today. Consider how rates will increase over 10 to 20 years with attained-age pricing.
Montana Medigap Rules You Should Know
No Birthday Rule or Anniversary Rule in Montana
Montana does not have a birthday rule or anniversary rule. Your 6-month Open Enrollment Period when you first turn 65 and enroll in Part B is your best opportunity to get Medigap coverage without medical underwriting. After that window, carriers can deny coverage or charge higher rates based on your health history.
Standard 6-Month Open Enrollment Period
Federal law gives you a 6-month Open Enrollment Period starting the month you turn 65 and enroll in Medicare Part B. During this window, no carrier can deny you coverage or charge higher premiums due to pre-existing conditions.
Attained-Age Rating Dominates
Most Montana Medigap carriers use attained-age pricing, meaning premiums increase as you age. Transamerica is a notable exception, offering issue-age pricing that locks your rate at enrollment.
Under-65 Coverage Not Required
Montana does not require Medigap carriers to offer coverage to Medicare beneficiaries under age 65 on disability. Some carriers offer coverage voluntarily, but availability and pricing vary.
Excess Charges Apply
Montana allows Medicare excess charges. Plan G covers these charges; Plan N does not. If your doctors do not accept Medicare assignment, Plan G provides more complete protection.
Free SHIP Counseling
Montana SHIP counselors provide free, unbiased help comparing Medigap plans. They never recommend specific policies or agents. Call (800) 551-3191 for assistance.
MedicareFAQ Scoring Methodology
The MedicareFAQ Score rates Medicare Supplement carriers on a scale of 1.0 to 5.0 based on five key factors. Our ratings are independent and not influenced by advertising relationships.
Financial Strength (AM Best)
Claims-paying ability and long-term stability
Customer Satisfaction
NAIC complaint ratios and member satisfaction surveys
Premium Competitiveness
Plan G and Plan N rates vs. Montana market average
Plan Availability
Number of plan types offered in Montana
Discounts and Value
Household discounts, EFT discounts, and added benefits
Last updated: May 2026 | Data sources: NAIC complaint ratios, AM Best ratings, CMS Medicare Plan Finder, Montana Commissioner of Securities and Insurance, FairSquare Medicare
Frequently Asked Questions
Find the Best Medigap Rate in Your Montana ZIP Code
Montana has no birthday rule, so your Open Enrollment Period is your best chance to lock in coverage without health questions. Plan G starts at $129/mo in Billings. Compare all available carriers in your area before enrolling.