In health insurance, the term “open enrollment” refers to a designated period of time during which the public can make changes to their coverage, with guaranteed enrollment.

The term “guaranteed enrollment” means that you cannot get turned down or charged more because of your medical history.

What Is the Purpose of Medicare Enrollment Periods?

The purpose of Medicare enrollment periods is to ensure that individuals have structured opportunities to enroll in or make changes to their Medicare coverage. These enrollment periods serve several key functions:

  • Timely Access to Coverage. Enrollment periods allow people to sign up for Medicare at the appropriate time, ensuring they have health insurance coverage when they become eligible or when they experience specific qualifying events.
  • Flexibility for Life Events. Special Enrollment Periods (SEPs) are triggered by certain life events, such as retirement, moving, or losing employer coverage. These SEPs ensure that individuals can adapt their Medicare coverage to their changing circumstances.
  • Supplemental Coverage. The Medigap Open Enrollment Period provides a window of opportunity for individuals turning 65 and enrolling in Medicare Part B to secure Medicare Supplement (Medigap) coverage without medical underwriting.

The Types of Medicare Open Enrollment Periods

When it comes to Medicare, “open enrollment” can refer to multiple different periods: 

  1. Medicare Initial Enrollment Period (IEP)
  2. Medicare General Enrollment Period
  3. Annual Enrollment Period
  4. Special Enrollment Periods
  5. 5-Star Special Enrollment Periods

Each of these periods applies to either Original Medicare (Medicare Parts A and B) or Medicare Advantage and Medicare Part D (prescription drug plans).

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Note that Medicare supplement insurance plans are not listed here. That’s because Medigap plans don’t have an annual enrollment period. You can apply for a Medigap plan at any time during the year. But enrollment after the initial Medigap enrollment period is not guaranteed. You could get turned down or charged more.

Let’s look at each of these four enrollment periods, in turn:

1. Medicare Initial Enrollment Period (IEP)

  • You have a guaranteed right to enroll in Medicare Parts A and B.
  • IEP dates are based on a 7-month period surrounding your birth month
    • IEP dates are based on a 7-month period surrounding your birth month
    • It continues through the month in which you turn 65.
    • Your IEP ends on the last day of the third month after your birth month.
    • If you still have coverage through your employer or your spouse’s employer, you can enroll in Part B late with no penalty.
    • Example: You turn 65 in July. Your IEP starts on April 1st and ends on November 30th.
    • Coverage start date:
      • If you enroll before your 65th birth month, your coverage starts on the first day of your birth month.
      • If you enroll in your birth month or later, coverage starts on the first day of the next month.
      • Keep this in mind if you are leaving your workplace plan or other coverage, to avoid a coverage gap.
  • Some people with certain chronic illnesses or disabilities, such as amyotrophic lateral sclerosis (Lou Gehrig’s Disease) and end-stage renal disease, qualify for  early enrollment in Medicare.

2. Medicare General Enrollment Period

  • Runs from January 1st through March 31st.
  • If you missed your Medicare Initial Enrollment Period, you have a right to enroll in Medicare during this period of time.
  • Late enrollment penalty may apply, unless you had coverage from another source, such as an employer plan or your spouse’s employer plan.
    • The late enrollment penalty is 10% of the Medicare Part B premium.
    • You’ll have to pay a 10% higher premium every month for as long as you live.
    • The government will take it out of your Social Security benefits.
  • Coverage begins July 1st.
  • If you need to enroll in Medicare Parts A and/or B during the General Enrollment Period, you also get a special enrollment period for Medicare Part D (prescription drugs).

3. Annual Enrollment Period (AEP)

  • Runs from October 15th through December 7th.
  • More formally referred to as the “Medicare Advantage and Prescription Drug Plan annual election period”
  • Allows you to change or switch from one Medicare Advantage plan to another.
  • Allows you to make changes to, add, or drop your Medicare Part D prescription drug plan.
  • Changes go into effect January 1st.

What can you do during AEP?

  • Switch from Original Medicare to a Medicare Advantage (MA)plan (or vice versa)
  • Switch to a different Medicare Advantage plan with or without prescription drug coverage
  • Switch from one Medicare Advantage plan to another
  • Join, switch, or leave a Medicare Part D prescription drug plan
  • Switching to a new private insurer

Learn More: The Medicare Fall Enrollment Period: What You Need to Know

4. Medicare Special Enrollment Periods

You may be entitled to a Medicare Special Enrollment Period if you have a qualifying life event.

Examples of qualifying events

  • You move your permanent residence out of your old Medicare Advantage plan’s service area.
  • You lose your employer coverage.
  • You are disenrolled from Medicaid
  • You are enrolled in a Medicare Advantage Special Needs Plan but no longer qualify as having special needs
  • Your plan is being discontinued in your area
  • You are released from incarceration
  • You are a non-citizen who becomes a permanent resident of the United States

5. 5-Star Special Enrollment Periods

  • Triggered only if there is a Medicare plan with a 5-star rating available serving in your area.
  • Runs from December 8th and November 30th of the following year
  • You have the right to switch from your current plan to the 5-star plan.

Confused? Need help joining a plan? No problem! Contact us today to schedule a free consultation from our experts.

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Whitney Kline is one of your Personal Benefits Managers at Medigap Advisors. She loves working for Medigap Advisors especially helping clients choose the right Medicare plan.