Original Medicare generally pays a portion of covered healthcare expenses, while the beneficiary may remain responsible for deductibles, coinsurance, and other amounts. Medigap can help cover some of these expenses depending on the plan selected.

Medigap is different from Medicare Advantage (Part C). Medicare Advantage is an alternative way to receive Medicare benefits through a Medicare-approved private plan, while Medigap supplements Original Medicare.

Generally, a person needs Medicare Part A and Part B to purchase a Medigap policy. Medigap policies are standardized by federal rules in most states, meaning plans with the same letter generally provide the same basic benefits regardless of the insurance company offering the policy.

Why Medicare Supplement Coverage Matters

Medigap can be relevant for people who want greater predictability around certain healthcare expenses under Original Medicare.

Potential reasons people consider Medigap include:

• Help with Medicare Part A and Part B coinsurance

• Help with certain deductibles

• Reduced exposure to some covered out-of-pocket expenses

• Potential foreign-travel emergency coverage under certain plans

• Ability to use Medicare-participating doctors and hospitals nationwide

• A standardized way to compare supplemental coverage

However, Medigap does not replace Medicare. You generally continue to have Original Medicare Part A and Part B, and Medicare remains the primary coverage for Medicare-covered healthcare.

Medigap also does not generally cover everything. Common exclusions include long-term care, routine dental or vision care, hearing aids, eyeglasses, private-duty nursing, and prescription drugs. Prescription drug coverage generally requires a separate Medicare Part D plan.

Medigap vs. Medicare Advantage

Understanding the difference between these two approaches is important before choosing coverage.

Medicare describes Original Medicare and Medicare Advantage as the two main ways beneficiaries can receive Medicare coverage. Medigap is an additional coverage option for people who choose Original Medicare.

Medigap Plan Types

Medigap policies are identified by letters. The benefits for a particular lettered plan are standardized in most states.

Common plan letters include:

• Plan A

• Plan B

• Plan C

• Plan D

• Plan F

• Plan G

• Plan K

• Plan L

• Plan M

• Plan N

Not every plan is necessarily available in every state.

The standardized structure makes it easier to compare similar plans from different insurers. The primary differences between companies offering the same standardized plan generally relate to factors such as the policy premium and company-specific underwriting or enrollment rules rather than the standardized benefits themselves.

Plans C and F: An Important Eligibility Rule

Plans C and F have special eligibility restrictions for people who became newly eligible for Medicare on or after January 1, 2020.

Medigap policies sold to people new to Medicare generally cannot cover the Medicare Part B deductible. Consequently, Plans C and F are not available to people who became newly eligible for Medicare on or after January 1, 2020.

People who were eligible for Medicare before that date may have different options, depending on their circumstances. Existing eligible policyholders can generally retain their qualifying Plan C or Plan F coverage.

What Medigap Generally Covers

Depending on the lettered plan, Medigap can help with certain expenses connected to Medicare-covered services.

Possible benefits include:

• Part A coinsurance

• Part B coinsurance

• Certain deductibles

• Hospital-related coinsurance after Medicare benefits are exhausted, depending on the plan

• Blood-related expenses in certain circumstances

• Hospice coinsurance or copayments

• Foreign-travel emergency coverage under certain plans

The exact benefits depend on the Medigap plan letter.

Medicare provides standardized benefit comparisons so beneficiaries can examine what each plan generally covers before making a decision.

What Medigap Generally Does Not Cover

Medigap should not be viewed as comprehensive health coverage for every healthcare need.

Generally excluded areas include:

• Prescription drugs

• Routine dental care

• Routine vision care

• Eyeglasses

• Hearing aids

• Long-term care

• Private-duty nursing

A separate Part D plan may be appropriate for prescription drug coverage when someone has Original Medicare and wants Medicare prescription coverage.

Medigap Open Enrollment Period

One of the most important Medigap rules concerns the 6-month Medigap Open Enrollment Period.

For people who are 65 or older, this period generally begins during the first month they have Medicare Part B. It is a one-time six-month period rather than an annual enrollment window.

During this period, a beneficiary generally has broader rights to purchase Medigap policies sold in the state. An insurance company generally cannot use medical underwriting to reject the application or charge more because of past or present health problems during this protected period.

This timing is important because protections can be different after the initial Medigap Open Enrollment Period ends.

What Happens After Medigap Open Enrollment?

After the six-month Medigap Open Enrollment Period, federal law generally does not guarantee that an insurer must accept a Medigap application.

Depending on the circumstances and state rules, an insurer may be able to:

• Decline an application

• Apply medical underwriting

• Charge a different premium

• Limit available policy options

There are exceptions known as guaranteed issue rights. These rights can apply in certain situations, such as losing qualifying health coverage or changing coverage under circumstances specified by Medicare law.

Because state rules can provide additional protections, beneficiaries should check with their State Health Insurance Assistance Program (SHIP) or State Insurance Department when evaluating enrollment rights.

Guaranteed Issue Rights

Guaranteed issue rights can protect certain people who need to obtain Medigap outside their normal Open Enrollment Period.

Situations can include specific circumstances involving:

• Losing certain employer or union coverage

• Leaving a Medicare Advantage plan under qualifying circumstances

• An insurer violating applicable rules

• Certain changes involving Medicare coverage

The precise rights depend on the individual's situation and applicable federal or state requirements.

Documentation may be required to demonstrate eligibility for guaranteed issue protections. Medicare recommends checking the specific circumstances rather than assuming that every coverage change creates a guaranteed issue right.

Medicare Enrollment and Medigap Timing

Medigap enrollment is connected closely to Medicare Part B enrollment.

Medicare's Initial Enrollment Period generally lasts seven months: three months before the month a person turns 65, the month they turn 65, and three months afterward.

If someone delays Part B because they have qualifying employer group health coverage, their Medigap Open Enrollment Period generally begins when they later enroll in Part B and meet the applicable age requirement.

This makes coordination between Medicare enrollment and supplemental coverage an important planning consideration.

Is Medicare Open Enrollment the Same as Medigap Open Enrollment?

No.

This distinction frequently causes confusion.

Medicare Open Enrollment, also called the Annual Enrollment Period, occurs from October 15 through December 7 each year. During this period, beneficiaries can make certain changes involving Medicare Advantage and Medicare prescription drug plans. Changes generally take effect January 1 of the following year.

The Medigap Open Enrollment Period is different. It is generally a one-time six-month period beginning when a person is 65 or older and first has Part B.

Therefore, the annual Medicare Open Enrollment Period does not automatically create a new six-month Medigap enrollment opportunity.

How Medigap Premiums Can Differ

Although standardized Medigap benefits are generally the same for the same plan letter, premiums can vary among insurance companies and individuals.

Factors that can influence premiums may include:

• Age

• Geographic location

• Plan letter

• Tobacco use

• Enrollment timing

• Pricing method used by the insurer

• Applicable state rules

Three common pricing approaches are:

Community-rated: People in a geographic area generally pay the same base premium regardless of age.

Issue-age-rated: The premium is based on age when the policy is first purchased.

Attained-age-rated: Premiums may increase as the policyholder becomes older.

State rules can affect how insurers price and structure Medigap policies.

Switching Medigap Policies

A person may sometimes decide that another Medigap plan better matches their circumstances.

However, switching policies can have consequences, particularly after the initial Medigap Open Enrollment Period.

Before changing policies, it is useful to review:

• Whether medical underwriting may apply

• Whether guaranteed issue rights exist

• Current and future premiums

• Differences in benefits

• State-specific protections

• Existing policy protections

• Whether prescription coverage is affected

• Effective dates of the old and new policies

Medicare recommends understanding the rules that apply to the individual's specific situation before changing supplemental coverage.

Medicare SELECT

Some states also have Medicare SELECT policies.

Medicare SELECT policies are a type of Medigap coverage that may require beneficiaries to use certain hospitals and, in some cases, doctors within a network to receive full benefits.

Federal rules provide certain protections for people who switch from Medicare SELECT to a standardized Medigap policy under qualifying circumstances.

Medigap and Prescription Drugs

Medigap policies sold after 2005 generally do not include prescription drug coverage.

If someone has Original Medicare and wants Medicare prescription coverage, they generally need to consider a separate Part D prescription drug plan.

A person cannot generally have prescription drug coverage through both a modern Medigap policy and a Medicare drug plan because Medigap policies do not provide current Part D coverage.

Medigap and Travel

Some Medigap plans provide benefits for certain emergency medical situations that occur outside the United States.

Travel-related benefits vary by plan, so international travelers should review the specific policy provisions rather than assuming every Medigap plan provides the same protection.

Medicare notes that some Medigap policies include foreign-travel emergency benefits.

Choosing a Medigap Plan

A structured comparison can make the decision easier.

Consider these factors:

• Which Medicare-covered expenses you want help with

• Whether you frequently travel

• Your preferred level of predictable healthcare expenses

• Whether you need separate prescription coverage

• Your state of residence

• Available plan letters

• Premium structure

• Insurer financial stability and policy administration

• Medical underwriting rules if outside Open Enrollment

• Future switching restrictions

It is also important to distinguish benefit differences from company differences. For standardized plans, the basic benefits associated with a letter are generally the same across insurers, while premiums and company-specific features can differ.

Tools and Resources

Useful official resources include:

• Medicare.gov — General Medicare and Medigap information

• Medicare Plan Finder — Compare available Medicare coverage options

• Medigap plan comparison resources — Review standardized benefits

• State Insurance Department — State-specific insurance rules

• SHIP — Free, unbiased Medicare counseling available through state programs

• Medicare & You handbook — Official annual Medicare reference

Medicare provides tools for finding Medigap policies available in a beneficiary's area and information about enrollment periods and coverage.

Recent Medicare Information for 2026

The 2026 Medicare & You handbook continues to identify the six-month Medigap Open Enrollment Period as a key protection for people who are 65 or older and newly enrolled in Part B. The handbook also notes that some states provide additional enrollment opportunities.

Medicare's current guidance also emphasizes that Medigap is designed to supplement Original Medicare rather than replace it. Beneficiaries should therefore consider Part A, Part B, prescription coverage, supplemental coverage, and other insurance together when planning their overall Medicare coverage.

FAQs

1. What is Medicare Supplement Insurance?

Medicare Supplement Insurance, or Medigap, is private insurance designed to help pay certain out-of-pocket expenses associated with Original Medicare Part A and Part B.

2. When is the best time to enroll in Medigap?

For people 65 or older, the federal Medigap Open Enrollment Period generally begins when Part B starts and lasts six months. During this period, federal protections generally provide broader access to Medigap policies without medical underwriting based on health conditions.

3. Does Medigap replace Medicare?

No. Medigap supplements Original Medicare. You generally continue to have Part A and Part B.

4. Does Medigap include prescription drug coverage?

Modern Medigap policies generally do not include prescription drug coverage. People with Original Medicare can generally consider a separate Part D plan for Medicare prescription coverage.

5. Can someone under 65 get Medigap?

Possibly, but federal law generally does not require insurers to provide Medigap to people under 65. Some states have additional protections or require insurers to provide certain Medigap options to people under 65 who qualify for Medicare because of disability or other circumstances.

6. Does Medicare Supplement cover dental and vision care?

Generally, Medigap does not cover routine dental or vision care, eyeglasses, or hearing aids.

7. Can Medigap coverage be used with Medicare Advantage?

Medigap is designed to supplement Original Medicare and generally isn't used with Medicare Advantage. If you choose Medicare Advantage, you generally use the benefits and rules of that plan instead.

Conclusion

Medicare Supplement Insurance can help people using Original Medicare manage certain out-of-pocket healthcare expenses. The most important concepts to understand are the differences between Medigap and Medicare Advantage, standardized plan letters, Part A and Part B eligibility, prescription coverage, and enrollment timing.

The six-month Medigap Open Enrollment Period is particularly important because it provides significant federal protections for eligible beneficiaries. After that period, options can depend on guaranteed issue rights, medical underwriting, and state-specific rules.

Reviewing Medicare's current information, comparing standardized benefits, and checking state-specific rules can help beneficiaries make more informed coverage decisions.