Medigap Enrollment Timing
When Is the Medicare Supplement Open Enrollment Period?
Your strongest federal opportunity to buy Medigap is a one-time six-month period tied to age 65 and Medicare Part B—not the fall Annual Enrollment Period.
Quick answer: Under federal law, your six-month Medigap Open Enrollment Period starts the first month you are both at least 65 and enrolled in Medicare Part B. During it, an insurer cannot use medical underwriting to deny you one of the Medigap policies it sells because of your health.
When Does Medigap Open Enrollment Start?
The start date depends on two conditions: you must be at least 65, and Medicare Part B must be active. The first month both conditions are true is month one of your six-month federal Medigap Open Enrollment Period.
Part B begins at 65
If your Part B coverage begins when you turn 65, your Medigap Open Enrollment Period normally begins that same month and continues for six months.
Part B is delayed
If you delay Part B because you have qualifying coverage based on current employment, the Medigap period generally begins later—when your Part B coverage starts and you are already at least 65.
Medigap enrollment timing can be especially important for someone who is still working. Do not start or delay Part B based only on a Medigap rule; first confirm how employer or union coverage coordinates with Medicare.
What Can You Do During the Six-Month Period?
During Medigap Open Enrollment, you may apply for any Medigap policy sold in your state for which you are otherwise eligible. The insurance company cannot refuse to sell you one of the policies it offers because of a current or previous health condition.
- Medical underwriting cannot be used to deny the application.
- The insurer cannot charge more because of past or present health problems.
- You can compare all standardized plan letters the company offers and for which you are eligible.
- You can compare the same plan letter across several insurance companies.
Standardized benefits, different premiums: A Plan G has the same standardized medical benefits regardless of the company selling it, but premiums, discounts, pricing methods, service and future rate changes can differ.
Is This the October 15–December 7 Enrollment Period?
No. Medicare’s fall Annual Enrollment Period is primarily used to join, leave or change Medicare Advantage and Part D coverage. It does not create a universal annual right to buy a Medicare Supplement without underwriting.
| Period | What it generally affects | Does it repeat? |
|---|---|---|
| Medigap Open Enrollment | Buying a Medicare Supplement with federal protections | One six-month period tied to age 65 and Part B |
| Annual Enrollment Period | Medicare Advantage and Part D elections | October 15–December 7 each year |
| Guaranteed-issue period | Certain Medigap choices after a qualifying event | Only when a specific federal or state right applies |
Do not assume fall enrollment solves a Medigap eligibility problem. A person can be allowed to leave Medicare Advantage during an election period and still face Medigap underwriting unless a separate open-enrollment, guaranteed-issue or state protection applies.
What Happens After Medigap Open Enrollment Ends?
You can still apply for a Medicare Supplement after the six-month period, but the outcome may be different. Unless a protected right applies, an insurance company may use medical underwriting where permitted.
Health questions
The application may ask about diagnoses, treatment, prescriptions, procedures or recent hospital care.
Different availability
A carrier may decline the application or offer fewer options if its underwriting requirements are not met.
Other rights
A guaranteed-issue event or an additional protection under state law may remove underwriting for specified policies.
Because the initial period normally cannot be changed or repeated, compare the coverage structure you want before it ends. Consider the plan letter, premium, pricing method, discounts, rate history, separate Part D needs and how easy it may be to change coverage later.
What Should You Have Ready?
- Your Medicare card and Part A and Part B effective dates
- Your preferred Medigap plan letter
- Current premium quotes from more than one carrier
- The policy’s rating method and available discounts
- A proposed effective date that coordinates with existing coverage
- A separate Part D comparison if you need outpatient prescription coverage
If you already have other medical coverage, do not cancel it until the Medigap policy is approved and the new effective date is confirmed.
Medigap Open Enrollment Questions
Does Medigap Open Enrollment happen every year?
No. The federal period is a one-time six-month period that begins when you are at least 65 and enrolled in Part B. Separate guaranteed-issue or state rights may provide other opportunities.
Can an insurer ask health questions during this period?
An application may contain health questions, but the insurer cannot use medical underwriting to deny the Medigap policy or change its price because of your health when you are in your federal Open Enrollment Period.
Does my period begin when I enroll in Part A?
Not by Part A alone. The federal Medigap period is tied to being at least 65 and enrolled in Medicare Part B.
What if I have Medicare before age 65?
Federal availability for people under 65 differs from the age-65 rule, and state law can provide additional rights. A new six-month federal Medigap Open Enrollment Period generally begins when you turn 65 and have Part B.
Can I delay Part B to delay my Medigap period?
Some people delay Part B while covered through current employment, but the Medicare consequences depend on the type of coverage. Confirm the Part B Special Enrollment Period and coordination rules before delaying.
Official Sources
Compare Medicare Supplement Options
Thompson Medicare Brokerage can help you compare plan benefits, premiums, enrollment rights and carrier options in Missouri and Illinois. Consultations are no-cost and no-obligation.
Thompson Medicare Brokerage is a non-government insurance agency. This page provides general educational information. Policy availability, premiums, underwriting, eligibility and enrollment rights vary by applicant, carrier, state and effective date.