You can switch supplement plans during specific windows, and missing them locks you in for a year

Medicare supplement plans (also called Medigap) let you change to a different plan or insurer during open enrollment periods and certain life events. Outside these windows, insurers can deny your switch or charge you more based on health conditions. The most important window is your initial enrollment period — the six months after you turn 65 and sign up for Medicare Part B. During this time, you can switch plans without medical underwriting, meaning the insurer cannot ask about your health or charge more because of pre-existing conditions.

After that initial window closes, your options narrow. You get a may provide right to switch during the annual open enrollment period (October 15 to December 7 each year), but only if you stay with the same insurer or switch to a plan in the same category. If you want to move to a different insurer or a plan that costs less, you may face medical underwriting — the insurer can review your health history and refuse to cover you, or charge a higher premium.

Key Takeaways

  • Your initial enrollment period — the six months after you turn 65 and enroll in Medicare Part B — is the only time you can switch plans without the insurer asking about your health.
  • During the annual open enrollment period (October 15 to December 7), you can switch to a different plan with the same insurer without medical underwriting, but switching insurers may require health review.
  • Certain life events (moving to a new state, losing employer coverage, becoming may be able to access for Medicaid) can open a special enrollment period outside the normal windows.
  • If you miss your initial enrollment period and do not have a may have access to life event, you may be locked into your current plan for a year and face higher premiums if you eventually switch.
  • Some states have additional protections that allow switching outside federal windows; check with your state insurance commissioner's office.

Your initial enrollment period: the six-month window with no health questions

The initial enrollment period runs for six months starting the month you turn 65 (or the month you become may be able to access for Medicare if you are older than 65). During this window, you can switch to any supplement plan offered by any insurer in your state, and the insurer must accept you without asking about your health or charging more because of pre-existing conditions. This is the only time you have this protection.

You do not have to wait until the first day of the month to switch. You can enroll at any point during the six-month window, and coverage typically begins on the first day of the month after the insurer receives your process. If you enroll on the 15th of a month, your new plan usually starts on the first day of the next month. Check with your insurer for their exact timeline, as it varies.

If you miss this window — for example, you turn 65 but do not enroll in a supplement plan until eight months later — you lose the may provide right to switch without medical underwriting. After the initial period ends, switching becomes harder and more expensive.

Annual open enrollment: what you can and cannot change

Every year from October 15 to December 7, you can switch supplement plans. However, what you can switch to depends on whether you are staying with your current insurer or moving to a new one.

If you stay with your current insurer, you can switch to any other supplement plan they offer without medical underwriting. The insurer cannot ask about your health or charge more because of pre-existing conditions. Your new coverage typically starts January 1 of the following year.

If you want to switch to a different insurer, the new insurer can require medical underwriting. They can review your health history, deny your request, or charge a higher premium. Some states limit this practice, but most do not. Before you switch insurers, contact the new company and ask whether they will underwrite your process based on health. If they say yes, you may want to stay with your current insurer instead.

Life events that open special enrollment periods

Certain changes in your circumstances can open a special enrollment period outside the regular windows. These events include moving to a new state, losing employer-sponsored coverage, becoming newly may be able to access for Medicaid or Extra Help, or having your current plan leave the market. During a special enrollment period, you usually have 60 days to switch plans, and the new insurer cannot use medical underwriting.

Moving to a new state is the most common trigger. If you relocate, your current supplement plan may not be available in your new state, or you may want to switch to a plan that works better in your new location. Contact your current insurer to confirm whether your plan is available where you are moving. If it is not, you have 60 days from the date you move to switch to a plan available in your new state without medical underwriting.

Losing employer coverage — for example, if your spouse retires and you lose coverage through their employer — also opens a special enrollment period. You have 60 days from the date coverage ends to switch plans. Bring documentation of the coverage loss (a letter from the employer or the plan administrator) when you explore.

Becoming newly may be able to access for Medicaid or Extra Help (the low-income subsidy for Part D) can also trigger a special enrollment period. Contact your state Medicaid office or the Social Security Administration to confirm the date your may be able to access began, then contact your new insurer within 60 days.

What happens if you miss all the windows

If you do not switch during your initial enrollment period, annual open enrollment, or a special enrollment period, you are locked into your current plan until the next annual open enrollment arrives. During this locked period, you cannot switch to a different plan or insurer without facing medical underwriting.

When you eventually do switch — during the next annual open enrollment or after a may have access to life event — the new insurer can ask detailed health questions and charge you a higher premium based on your answers. Some insurers will deny your process outright if you have certain conditions. This is called a pre-existing condition exclusion, and while federal law limits how long insurers can enforce it, the practical effect is that switching becomes expensive or impossible.

To avoid this trap, mark your calendar for October 15 each year. Even if you are happy with your current plan, review your options during annual open enrollment. Rates change, and a different plan or insurer may offer better coverage or lower premiums. You have until December 7 to switch, and the new coverage starts January 1.

State-specific rules that may help you switch

Some states have enacted their own rules that give you more flexibility than federal law requires. For example, a few states allow you to switch supplement plans twice per year instead of once. Others have rules that limit how much insurers can charge based on health history, or that require insurers to accept all applicants during certain periods.

Your state insurance commissioner's office maintains a list of these protections. You can find contact information on the National Association of Insurance Commissioners website, or search "[your state] insurance commissioner supplement plans" online. Call and ask whether your state allows switching outside the federal windows, or whether there are limits on medical underwriting in your state.

If you live in a state with stronger protections, you may have more options than someone in a state that follows only federal rules. It is worth checking, especially if you missed a federal enrollment window and are locked into a plan you want to leave.

How to switch plans during an open window

Once you confirm you are in an open enrollment period or have a may have access to life event, contact the new insurer directly. You can find supplement insurers in your state through Medicare.gov or by calling 1-800-MEDICARE. Ask the insurer for their process form and a summary of the plan you are interested in.

You will need your Medicare card, Social Security number, and information about your current coverage (plan name and policy number). If you are switching because of a life event, have documentation ready: a lease or utility bill showing your new address if you moved, a letter from your employer if you lost coverage, or a Medicaid approval letter if you became may be able to access for Medicaid.

Submit the process to the new insurer. Most insurers accept applications by mail, phone, or online. Ask when your new coverage will start — it is usually the first day of the month after the insurer receives your process, but some insurers have different timelines. Once your new plan is approved and active, contact your old insurer to cancel your previous supplement plan. Do not cancel until you confirm your new coverage is in effect.

Frequently Asked Questions

Can I switch supplement plans if I am already on Medicare?

Yes, but only during open enrollment periods or if you have a may have access to life event. If you are outside these windows and do not have a may have access to event, the new insurer can require medical underwriting and may deny your process or charge more based on your health history.

What counts as a may have access to life event?

Moving to a new state, losing employer coverage, becoming newly may be able to access for Medicaid or Extra Help, and having your current plan leave the market are the main triggers. Some states recognize additional events. Contact your state insurance commissioner's office to confirm what qualifies in your state.

If I switch plans, do I lose coverage during the transition?

No. Your new plan typically starts on the first day of the month after the insurer approves your process. Your old plan remains active until then. Do not cancel your old plan until your new coverage is confirmed and in effect.

Can an insurer charge me more if I switch during annual open enrollment?

If you stay with your current insurer, no — they cannot charge more based on health. If you switch to a different insurer, they can charge more based on medical underwriting, unless you have a may have access to life event or live in a state with additional protections.

What if my supplement plan is no longer available?

If your insurer discontinues your plan, you have a special enrollment period to switch to a different plan without medical underwriting. The insurer must notify you in writing at least 30 days before the plan ends. Contact your insurer or a new insurer within 60 days of the notice to switch plans.