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Medicare’s special enrollment periods

The rules involving Medicare's SEPs vary depending on whether you have Part A or Part B, Medicare Advantage, Part D or Medigap.

Louise Norris | July 13, 2023

Reviewed by our health policy panel.

Like other types of health insurance, Medicare has special enrollment periods triggered by various qualifying life events. But the rules for special enrollment periods vary depending on whether we’re talking about Medicare Part B (and Part A, if you have to pay a premium for it), Medicare Advantage and Part D, or Medigap. This article will provide an overview of how special enrollment periods work for each of these types of Medicare coverage.

Medicare Part B special enrollment period

If you’re aging into Medicare, you can enroll during your seven-month initial enrollment period (IEP). If you miss that window, you have an annual opportunity to sign up for coverage during the January – March general enrollment period. (A late-enrollment penalty will apply if you’ve delayed your enrollment by at least 12 months from when you were initially eligible.) But if you qualify for a special enrollment period, you don’t have to wait for the general enrollment period, and you may also be able to avoid late-enrollment penalties.

A special enrollment period for Medicare Part B (and Part A, if you have to pay for it) is available if you’ve delayed your enrollment because you (or your spouse) are still working and you’re covered by an employer’s group health plan. You can enroll in Part B at any point while you still have coverage under that plan as an active employee or spouse of an active employee. (Retiree coverage or COBRA will not provide access to this special enrollment period.) And the special enrollment period continues for eight months after the final month of employment or coverage (if the coverage ends before employment ends), with the eight-month window starting with whichever of those events happens first.

Note that COBRA or retiree benefits do not count as active coverage based on employment. And individual/family coverage purchased through the exchange or directly from an insurer will not allow you to qualify for the Part B special enrollment period. Learn more about how you can delay Part B without a penalty.

For most Medicare beneficiaries, there’s no premium for Medicare Part A, and thus no reason to delay enrollment. (You can’t contribute to an HSA once you’re enrolled in any part of Medicare, so some people do delay Part A in order to continue to contribute to an HSA.)

But Part B has a monthly premium ($164.90/month for most enrollees in 2023) so people do sometimes choose to delay enrollment in Part B. As long as they’re covered under an employer’s health plan as an active employee or spouse of an active employee, they will have an opportunity to sign up for Part B once they no longer have active employee coverage.

There is also a Part B (and Part A, if premiums are required) special enrollment opportunity for a person who was serving overseas for at least 12 months as a volunteer with a 501(c)(3) tax exempt organization when they first became eligible for Medicare, assuming they had health coverage during the time they were volunteering. They have a six-month window, starting when they return to the U.S., during which they can enroll in Medicare.

And finally, there is a 12-month special enrollment period for people with TRICARE coverage who become eligible for Medicare prior to age 65, but don’t enroll when they’re first eligible. The special enrollment period begins when their initial enrollment period ends, and continues for 12 months.

As outlined in this rule-making document, the special enrollment periods described above were the only ones that were specifically available prior to 2023. The equitable relief process could be used in certain circumstances to allow a person to enroll outside of their initial enrollment period or the general enrollment period, but there were no other designated special enrollment periods for Part B (or Part A, for people who pay a premium). But that changed as of 2023.

New Medicare special enrollment periods in 2023

In addition to the long-standing Medicare special enrollment periods described above, some new Medicare special enrollment periods became effective as of 2023 under rules that were finalized in late 2022. There are several circumstances that will now trigger a special enrollment period during which a person can enroll in Medicare Part B (and Part A, if they have to pay a premium for it) right away, without a late-enrollment penalty:

  • You missed a normal Medicare enrollment opportunity because you were affected by a government-declared emergency or disaster. The special enrollment periods lasts for six months after the end of the emergency/disaster declaration.
  • You didn’t enroll in Medicare during a normal enrollment opportunity because you were given incorrect information by your employer, group health plan, or agent/broker representing the group health plan. The special enrollment period lasts for six months, starting with the date you notify the Social Security Administration of the error.
  • You’re released from incarceration, after either becoming eligible for Medicare while incarcerated, or losing Medicare during incarceration. The special enrollment period continues for 12 months after you’re released.
  • You didn’t enroll in Medicare when you were first eligible because you were enrolled in Medicaid and the Medicaid coverage was allowed to continue. This was the case for some people during the COVID pandemic, when Medicaid disenrollments were generally prohibited. The special enrollment period lasts for six months after Medicaid ends.
  • If you have extenuating circumstances that prevented you from enrolling in Medicare during a normal enrollment opportunity, CMS can grant special enrollment periods on a case-by-case basis.

Any special enrollment right to sign up for Medicare Part B (and Part A, if you have to pay a premium for it) will allow you to choose either Original Medicare or Medicare Advantage.

Medicare Advantage and Part D special enrollment periods

If you’re enrolled in a Medicare Advantage or Part D plan, you can make changes to your coverage during an annual election period (open enrollment period) each fall.

But there are a variety of qualifying life events that will allow you to switch to a different plan outside of the annual election period. (Depending on the circumstances, there may also be an option to switch to Original Medicare.) Here are situations considered qualifying life events:

  • You make a permanent move – to a location that’s either outside your plan’s service area, or to an area where the are other Medicare Advantage or Part D plans available. It can also be a move back into the United States after living abroad, a move into or out of an institution, or your release from incarceration. In general, the special enrollment period continues for two months after your move, and it can also start the month before, depending on the circumstances.
  • You lose other health coverage. The coverage you’re losing can be Medicaid, or employer or union-sponsored coverage (including COBRA). It can also be involuntary loss of other creditable drug coverage, or leaving a Medicare Cost Plan or Program for All-Inclusive Care for the Elderly (PACE) plan. In general, your special enrollment period will last for at least two months after the other coverage ends. You’ll have the opportunity to join a Medicare Advantage or Part D plan, or, if applicable, switch to a different plan.
  • You have an opportunity to enroll in other coverage. This could be an opportunity to enroll in an employer’s plan, an opportunity to enroll in other creditable drug coverage, or enrolling in a PACE plan. You have a special enrollment period that will allow you to drop your current Medicare Advantage or Part D plan and switch to the other coverage.
  • Your plan’s contract with Medicare is terminated, non-renewed, or sanctioned. You’ll have an opportunity to enroll in a different Medicare Advantage or Part D plan. (In the case of a contract sanction, the special enrollment opportunity will be determined by CMS on a case-by-case basis.)
  • You have both Medicare and Medicaid. This gives you an opportunity to join, switch, or disenroll from a Medicare Advantage or Part D plan up to one time per quarter. (For the final quarter of the year, the regular October 15 – December 7 annual election period applies instead).
  • You’re eligible for Extra Help. This gives you a quarterly opportunity to join, switch, or disenroll from a Part D plan (for the final quarter of the year, the regular October 15 – December 7 annual election period applies instead).
  • You’re enrolled in a State Pharmaceutical Assistance Program (SPAP). You have one annual opportunity to enroll in a Part D plan or a Medicare Advantage plan that includes Part D coverage.
  • You have a chronic, severe, or disabling medical condition and there’s a special needs plan (SNP) available in your area for people with your medical condition. You can switch to that plan at any time. On the other hand, if you’re enrolled in an SNP and then you no longer have the condition that the SNP is designed to serve, you can transition away from the SNP and to another Medicare Advantage or Part D plan.
  • You received erroneous advice or information. This can include the fact that you enrolled in (or didn’t enroll in) a plan due to a federal employee’s error, which will allow you to join, switch, or drop your Medicare Advantage or Part D plan. Or it could be a situation in which you weren’t informed that your private drug coverage wasn’t as good as Medicare coverage (wasn’t creditable) or you weren’t informed that you would be losing creditable drug coverage. In either of those two scenarios, you’ll have a special enrollment right to enroll in Part D coverage, either as a stand-alone plan or as part of a Medicare Advantage plan.

Medigap special enrollment periods

Medigap (Medicare supplement insurance) is unique among the various types of Medicare coverage, in that it does not have a federally mandated annual enrollment period.

Some states do have limited annual enrollment opportunities, but federal rules only require all Medigap plans to be guaranteed-issue during a six-month window that starts when a person is at least 65 and enrolled in Medicare Part B. (You must also be enrolled in Part A in order to buy a Medigap plan, but the six-month window starts with your Part B effective date, assuming you’re at least 65 years old.)

After that, Medigap insurers in most states can use medical underwriting when a person applies for Medigap coverage. That means the insurer can reject the application or offer a policy with a higher premium, depending on the person’s medical history.

But there are certain situations where an insurance company can’t deny you a Medigap policy (or charge higher premiums based on medical underwriting), which are referred to as guaranteed-issue rights. (Unlike other types of Medicare coverage, a beneficiary can apply for a Medigap plan at any time, but the insurer can use medical underwriting if the person doesn’t have a guaranteed-issue right.)

In general, the guaranteed-issue special enrollment period continues for 63 days after the qualifying event, and in some cases it’s also available starting 60 days before the qualifying event. In most cases, a guaranteed-issue right will only allow you to enroll in Medigap Plan A, B, C, D, F, G, K, or L, as opposed to any available Medigap plan. (Note that regardless of the circumstances, Plans C and F can only be purchased by people who became eligible for Medicare prior to 2020.)

There are a variety of qualifying circumstances that result in a federal Medigap guaranteed-issue right. They include:

  • Trial right: You joined a Medicare Advantage or PACE plan when you were first eligible for Medicare, and you’ve been enrolled in that plan for less than a year. You’re in your trial right period, and have the option to switch to any available Medigap plan.
  • Trial right: You dropped a Medigap policy and switched to a Medicare Advantage plan for the first time and have been enrolled in the new plan for less than a year. You’re in your trial right period and can switch back to the Medigap plan you had before. If it’s no longer available, you can switch to any available Medigap Plan A, B, C, D, F, G, K, or L.
  • Medicare Advantage plan no longer available: You have Medicare Advantage and your plan terminates its contract with Medicare, stops offering coverage in your area, or you move out of the plan’s service area. You have the right to buy any available Medigap Plan A, B, C, D, F, G, K, or L.
  • Other health coverage is ending. Other health coverage is ending. You have Original Medicare and employer-sponsored coverage (including COBRA) and the employer-sponsored plan is ending. You have the right to buy any available Medigap Plan A, B, C, D, F, G, K, or L.
  • Moving out of your Medicare SELECT plan’s service area. Medicare SELECT is a type of Medigap that has a localized provider network. If you have this type of coverage and move out of the plan’s service area, you have the right to buy any available Medigap Plan A, B, C, D, F, G, K, or L.
  • Involuntary loss of your Medigap coverage. If your Medigap carrier goes bankrupt or you otherwise lose your coverage through no fault of your own (note that loss of coverage due to failure to pay premiums does not trigger a special enrollment period). You have the right to buy any available Medigap Plan A, B, C, D, F, G, K, or L.
  • Rule breach by your Medicare Advantage or Medigap plan. If you left your Medicare Advantage or Medigap plan because the plan misled you or didn’t follow Medicare’s rules, you have the right to buy any available Medigap Plan A, B, C, D, F, G, K, or L.

As noted above, some of these qualifying life events will also trigger a special enrollment period to sign up for a Medicare Advantage plan. You’ll want to consider the pros and cons of Medigap plus Part D versus Medicare Advantage before making your decision.


Louise Norris is an individual health insurance broker who has been writing about health insurance and health reform since 2006. She has written dozens of opinions and educational pieces about the Affordable Care Act for healthinsurance.org since 2013. Her state health exchange updates are regularly cited by media who cover health reform and by other health insurance experts.

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