If you're having a hard time understanding the different enrollment periods for original Medicare, Medicare Part D, and Medicare Advantage, you're not alone. Our comprehensive charts break down the Medicare enrollment periods in simple terms—including when they take place, what beneficiaries can do, and when any changes to their coverage will occur.
Use this information to help the older adults you serve make timely decisions about their health care coverage—and avoid the financial penalties that may result in not signing up on time.
What are the different Medicare enrollment periods?
The periods during which beneficiaries can make changes to their coverage are:
- Annual Medicare Advantage Open Enrollment Period
- General Enrollment Period
- Annual Open Enrollment Period
- Initial Enrollment Period
- Special Enrollment Periods
- Medigap Open Enrollment Period
These enrollment periods are outlined in detail below.
Key Enrollment Periods for People With Medicare | ||
Annual Medicare Advantage Open Enrollment PeriodJan. 1 – March 31 | ||
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Who Is It For? |
What Beneficiaries Can Do |
When Does Coverage Start? |
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People already enrolled in a private Medicare Advantage (Part C) plan as of January 1 who wish to switch plans or leave their plan to get original Medicare (Parts A and B) |
• Switch Medicare Advantage plans • Disenroll from Medicare Advantage to go to original Medicare (can also pick up a Part D drug plan) |
First day of the month following the month of enrollment (i.e., if they apply in January, coverage starts Feb. 1) |
Annual Open Enrollment PeriodOct. 15 –Dec. 7 | ||
| Who Is It For? | What Beneficiaries Can Do | When Does Coverage Start? |
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Anyone who is enrolled in Medicare Parts A and/or B, including those who may already be enrolled in a Medicare Advantage or Part D plan |
• Change from original Medicare to a private Medicare Advantage plan • Change from Medicare Advantage to original Medicare • Join, drop, or switch Part D drug plans • Switch Medicare Advantage plans |
Jan. 1 |
Special Enrollment Period (SEP)Ongoing (SEPs exist for people to enroll in Parts A and B, and to enroll in/switch Medicare Advantage and Part D plans) | ||
| Who Is It For? | What Beneficiaries Can Do | When Does Coverage Start? |
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There are numerous SEPs for both Medicare Parts A and B, Part D and Medicare Advantage plans. New Part A and B SEPs provide relief to people who miss a Medicare enrollment period due to an exceptional condition such as: • Impacted by an emergency or disaster • Health plan or employer error • Formerly incarcerated people • Coordinate with termination of Medicaid coverage Part D and MA SEPs can apply to those who: • Lose active employee/spousal coverage (and didn’t sign up for original Medicare when first eligible) • Move out of a plan’s service area (for Medicare Advantage and Part D plans) • Enter or leave an institution (nursing home, jail) • Qualify for the Part D Low-Income Subsidy (Extra Help) |
• Join Part A and Part B • Change/enroll in a Part D plan • Change/enroll in a Medicare Advantage plan Note: Specific rules and timing apply to SEPs based on a person’s individual circumstances. Learn more from Medicare. |
Varies; see Medicare link at left for more details |
Medigap Open Enrollment Period (OEP)Ongoing (6-month window after a person enrolls in Part B) | ||
| Who Is It For? | What Beneficiaries Can Do | When Does Coverage Start? |
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People turning 65, newly eligible for Medicare, and enrolled in Parts A and B |
• Can purchase a Medigap policy without medical underwriting Learn more in our fact sheet: Medigap Open Enrollment Period |
First day of the following month |
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General Enrollment PeriodJan. 1 – March 31 | ||
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Who Is It For? |
What Beneficiaries Can Do |
When Does Coverage Start? |
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People who did not sign up for Medicare Parts A and/or B when first eligible and who do not have a Special Enrollment Period |
• Sign up for Medicare Parts A and B |
First day of the month following the month of enrollment |
Initial Enrollment Period (IEP)Ongoing (seven-month window around 65th birthday, or for those under 65 and found to have a disability, generally the month after a 24-month “waiting period”) | ||
| Who Is It For? | What Beneficiaries Can Do | When Does Coverage Start? |
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People newly eligible for Medicare, both those turning 65 and those under 65 who are found to have a disability by Social Security and have met their Medicare “waiting period” (i.e., received SSDI benefits for 2 years) |
• Join Medicare Parts A and/or B, and also enroll in Part D |
No earlier than month of Medicare eligibility; see Medicare & You handbook for more information |
Medicare Advantage Open Enrollment Period within Initial Coverage Election Period (ICEP)The month of entitlement to Parts A and B through the last day of the ICEP or third month of entitlement | ||
| Who Is It For? | What Beneficiaries Can Do | When Does Coverage Start? |
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People newly eligible for Medicare |
• Can enroll in a Medicare Advantage plan, with or without drug coverage |
First day of the month following the month of enrollment (and the person is enrolled in both Parts A and B) |
Where can older adults get help choosing Medicare coverage?
There are a lot of factors to consider when choosing a Medicare plan. The good news is older adults don’t have to search for plans on their own. State Health Insurance Assistance Programs (SHIPs) offer free, unbiased help with Medicare coverage selection. People can find their local SHIP by calling 1-877-839-2675 or visiting their website.
Older adults can also get help navigating their options from Medicare brokers that meet NCOA’s Standards of Excellence (SOE). These experts will provide straightforward, tailored advice without pressuring them into buying a certain Medicare plan. Learn more about our trusted partners.
Need Help Understanding Medicare Enrollment?
Timing is critically important when it comes to enrolling in Medicare. If you think you will want Medicare at any point in your life—and you most likely will—you need to understand when you can and should enroll.
