Medicare in Idaho

Medicare enrollment in Idaho

As of February 2026, 411,684 Idaho residents were enrolled in Medicare.¹

Most individuals become eligible for Medicare when they turn 65. But Medicare also provides coverage for younger individuals after they have been receiving disability benefits for 24 months or have been diagnosed with amyotrophic lateral sclerosis (ALS) or end-stage renal disease (ESRD). People with these diagnoses do not have to wait two years for their Medicare enrollment to start.

Both in Idaho and nationwide about 9% of Medicare beneficiaries are eligible due to disability rather than age.²³

• Read about Medicare’s open enrollment period and other important enrollment deadlines.
• Learn how Idaho’s Medicaid program can provide assistance to Medicare beneficiaries with limited income and assets.

Medicare Advantage plan availability and enrollment in Idaho

Medicare Advantage plans are offered by private insurers that each have their own service area, so plan availability varies from one part of the state to another. In 2026, Medicare Advantage plans are available in all areas of Idaho except Butte County. The average Medicare beneficiary in Idaho can choose from among 15 Medicare Advantage plans in 2026.⁴

As of early 2026, about 46% of all Idaho residents with Medicare were enrolled in private Medicare Advantage plans.² As of February 2026, there were 189,135 Idaho residents with private Medicare Advantage coverage.²

Sources: Medicare Advantage 2026 Spotlight: A First Look at Plan Offerings, KFF.org, Dec. 9, 2025; Fact Sheet: Medicare Open Enrollment for 2026, Centers for Medicare & Medicaid Services. Sep. 26, 2025

Learn more about Medicare Advantage, Medicare’s annual open enrollment period, and the Medicare Advantage open enrollment period.

Medicare supplement (Medigap) plan availability in Idaho

As of 2024, there were 94,313 Idaho Medicare beneficiaries with Medigap coverage, according to an AHIP analysis.⁵

There are 21 insurance companies in Idaho that offer Medigap plans for 2026.⁶

Learn how Medigap plans are standardized and what they cover.

Idaho state law requires Medigap insurers to spend at least 65% of premiums (75% for group plans) on benefits for enrollees, as opposed to administrative costs. And since March 2022, Idaho’s Medigap insurers have been required to use community rating for new policies (meaning that rates don’t vary by age or gender), due to legislation that was enacted in 2021.⁷

(In many states, insurers have the option of using attained-age rating, issue-age rating, or community rating. Idaho had banned attained-age rating since 1995,⁸ and the 2021 legislation also prohibited issue-age rating.)

Idaho is one of nine states that require Medigap insurers to use community rating.⁹

Under the same 2021 legislation that prohibited issue-age rating for Medigap policies, the Idaho Department of Insurance was allowed to establish an annual window when people with Medigap coverage can switch to a different Medigap plan on a guaranteed-issue basis. The proposed rulemaking on this was issued in September 2021, and was finalized in late 2021.

Idaho’s “birthday rule” took effect in 2022. It allows people who already have Medigap coverage to switch to any other Medigap plan – of equal or lesser benefits – during a 63-day window that starts each year on their birthday.¹⁰

For perspective, unlike other private Medicare coverage (Medicare Advantage and Medicare Part D plans), there is no federal annual open enrollment window for Medigap plans. Instead, federal rules provide a one-time six-month window when Medigap coverage is guaranteed-issue. This window starts when a person is at least 65 and enrolled in Medicare Part B (you must be enrolled in both Medicare Part A and Part B to buy a Medigap plan). It’s important to secure coverage during this window. If you submit an application later on, Medigap insurers are allowed to use medical underwriting to determine your eligibility for coverage.

To clarify, the “birthday rule” does not allow a person to newly enroll in Medigap coverage without medical underwriting after their initial enrollment window has ended. It only allows people who already have Medigap to make a plan change. But that’s an important consumer protection that doesn’t exist in the majority of states.

Are Medigap plans available for beneficiaries under age 65 in Idaho?

People who aren’t yet 65 can enroll in Medicare if they’re disabled and have been receiving disability benefits for at least two years or if they have amyotrophic lateral sclerosis (ALS) or end-stage renal disease (ESRD), which is the case for about 9% of Idaho’s Medicare beneficiaries.¹¹ Federal rules do not guarantee access to Medigap plans for people who are under 65, but the majority of the states have implemented rules to ensure that disabled Medicare beneficiaries have at least some access to Medigap plans. Idaho joined those states in 2018, with changes to Idaho insurance statute that took effect January 1, 2018.

Idaho Medigap insurers are required to offer their plans to disabled Medicare beneficiaries under age 65, with the same six-month open enrollment period that applies to people who gain eligibility for Medicare due to age. (There’s a six-month window when the person is first enrolled in Medicare Part B, during which they can enroll in any Medigap plan, guaranteed issue, regardless of age). Idaho’s new rule included a provision to grant a one-time six-month Medigap open enrollment window (January through June 2018) to people who were under age 65 and already enrolled in Medicare at that point.

In addition, Idaho’s rule limits the premiums for under-65 Medigap to no more than 150% of the premiums that apply to a person who is 65 years old. (See 2026 premiums for a non-smoker under age 65, and for a non-smoker who is age 65.) This is an important provision: some states that require Medigap plans to be offered to people under age 65 do not limit premiums and insurers end up charging several times as much as they charge 65-year-old enrollees.

As noted above, Idaho requires community rating for all new Medigap enrollees, which means premiums for people 65+ no longer vary by age. But the state still allows Medigap insurers to charge up to 150% of that community-rated amount if the beneficiary is under age 65.¹²

Disabled Medicare beneficiaries have another Medigap open enrollment period when they turn 65. At that point, they can switch to a plan with the lower premiums that apply to people who are aging into Medicare, rather than qualifying due to disability.

Learn how Medigap plans are regulated and standardized.

Medicare Part D plan availability and enrollment in Idaho

There are 10 stand-alone Medicare Part D plans for sale in Idaho for 2026, with premiums that start at $0/month.¹³

As of February 2026, there were 154,509 Idaho Medicare beneficiaries with stand-alone Medicare Part D plans. Another 168,541 had Medicare Part D prescription coverage as part of their Medicare Advantage plans.²

Learn how Medicare Part D prescription drug coverage works, what it pays for, how and when to enroll.

Source: Fact Sheet: Medicare Open Enrollment for 2026, Centers for Medicare & Medicaid Services. Sep. 26, 2025

Resources for Medicare beneficiaries in Idaho

Have questions about Medicare enrollment or Medicare eligibility in Idaho?

• SHIBA, Idaho’s Senior Health Insurance Benefits Advisers, provides a variety of helpful information, including a series of Medicare FAQs.
• The Idaho Department of Insurance has a Medigap resource page that includes links to current premium charts.
• The Medicare Rights Center has a comprehensive national website and a helpful call center that can provide a variety of assistance with Medicare-related questions.
• Programs of All-Inclusive Care for the Elderly (PACE): A Medicare/Medicaid program that helps seniors receive the care they need in their homes and local communities, without having to move into a nursing home.