Understanding Medicare Enrollment Periods
When Can I Enroll in Medicare?
Navigating Medicare enrollment can feel complex, but understanding the different enrollment periods is key to getting the coverage you need. There are several Medicare enrollment periods throughout the year, each designed for specific situations and life events.
Whether you're new to Medicare, looking to change your coverage, or experienced a qualifying life event, Healthpilot's guide exists to explain every Medicare enrollment period and when you can make changes to your Medicare Advantage (Part C), Part D prescription drug coverage, or Original Medicare plan.
Medicare Enrollment Periods Reference Chart
| Enrollment Period | Dates | Who Can Use It | What You Can Do |
|---|---|---|---|
| Initial Enrollment Period (IEP) | 7 months around 65th birthday | First-time Medicare enrollees | Enroll in Parts A, B, C, and D |
| General Enrollment Period (GEP) | January 1 - March 31 | Those who missed IEP | Enroll in Parts A and B (coverage starts first day of the month after you enroll) |
| Annual Enrollment Period (AEP) | October 15 - December 7 | Everyone with Medicare | Change Medicare Advantage, Part D, or switch between Original Medicare and MA |
| Medicare Advantage Open Enrollment (MA OEP) | January 1 - March 31 | Current Medicare Advantage members only | Make one change to MA plan or return to Original Medicare |
| Initial Coverage Election Period (ICEP) | Varies (around Part B start) | New Medicare enrollees | Enroll in Medicare Advantage when first eligible |
| Special Enrollment Periods (SEP) | Year-round, situation-dependent | Those with qualifying life events | Enroll or change coverage based on specific circumstances |
Initial Enrollment Period
7-month Window Around Your 65th BirthdayYour Initial Enrollment Period is your first opportunity to enroll in Medicare.
This 7-month period includes:
3 months before
65th Birthday Month
3 months after
What You Can Do During IEP
- Enroll in Medicare Part A (hospital insurance)
- Enroll in Medicare Part B (medical insurance)
- Join a Medicare Advantage plan (Part C) once you have enrolled in Parts A and B
- Add Medicare Part D prescription drug coverage
When Will My Coverage Start?
- Enroll 3 months before your birthday: Coverage begins the first day of your birthday month.
- Enroll during your birthday month: Coverage begins the first day of the following month.
- Enroll in the 3 months after: Coverage begins the first day of the following month.
Important: If you miss your Initial Enrollment Period and don't have creditable coverage, you may face lifetime late enrollment penalties for Part B and Part D coverage.
Annual Enrollment Period
October 15 to December 7 each year
The Annual Enrollment Period (AEP), also commonly called Open Enrollment or Fall Open Enrollment, is Medicare's main opportunity for everyone with Medicare to review and change their coverage. This is when most people make changes to their Medicare plans.
Why Different Names For The Same Period?
You might hear this enrollment period referred to by several names:
- Annual Enrollment Period (AEP) is the official Medicare term
- Open Enrollment Period is commonly used by beneficiaries and insurance agents
- Fall Open Enrollment references the October-December timeframe
- Annual Election Period is an older official term that is still sometimes used
What You Can Do During AEP
- Switch from Original Medicare to a Medicare Advantage plan
- Switch from a Medicare Advantage plan back to Original Medicare
- Join, switch, or drop a Medicare Advantage plan
- Join, switch, or drop a Medicare Part D prescription drug plan
When Will My Coverage Start?
All changes made during the Annual Enrollment Period take effect on January 1 of the following year.
Why Review Your Coverage During AEP
Healthcare needs change. Your plan's costs, coverage, and provider networks may also change from year to year. The Annual Enrollment Period ensures you can:
- Adjust coverage to match current health needs
- Compare new plan options in your area
- Switch plans if yours is being discontinued
- Find better prescription drug coverage as your medications change
- Reduce out-of-pocket costs if you've found a more affordable option
Initial Coverage Election Period
For enrolling in Medicare Advantage when you first get MedicareThe Initial Coverage Election Period is your first opportunity to enroll in a Medicare Advantage plan after you become eligible for Medicare. Understanding ICEP is important because the timeframe varies based on when you enroll in Medicare Part B.
Standard ICEP (If you enroll in Part B during your IEP): If you enroll in Medicare Part B during your 7-month Initial Enrollment Period, your ICEP runs:
3 months before
65th Birthday Month
3 months after
This aligns with your Initial Enrollment Period for Parts A and B, giving you a full 7 months to decide on a Medicare Advantage plan.
Delayed Part B ICEP Period
3 months before
Part B Effective Date
If you delay enrolling in Medicare Part B (for example, if you have employer coverage), your Initial Coverage Election Period is only the 3 months before your Part B effective date.
This is shorter than the standard ICEP, so timing is especially important. You'll want to submit your Medicare Advantage enrollment application within those 3 months before your Part B coverage begins.
When Will My Coverage Start?
Your Medicare Advantage plan becomes effective the same month your Medicare Part B coverage takes effect.
Confused About IEP vs. ICEP?
- IEP (Initial Enrollment Period): When you first sign up for Original Medicare Parts A and B
- ICEP (Initial Coverage Election Period): When you first enroll in a Medicare Advantage plan (Part C)
Medicare Advantage Open Enrollment Period
January 1st to March 31st each year
The Medicare Advantage Open Enrollment Period gives beneficiaries who are already enrolled in a Medicare Advantage plan one more opportunity to adjust their coverage after the new year begins.
This period only applies to people currently enrolled in a Medicare Advantage plan. If you have Original Medicare only, this period does not apply to you.
What You Can Do During MA OEP
- Switch to a different Medicare Advantage plan (one time only during this period)
- Drop your Medicare Advantage plan and return to Original Medicare
- Add a standalone Medicare Part D prescription drug plan if you switch back to Original Medicare
What You Cannot Do During MA OEP
- Switch from Original Medicare to a Medicare Advantage plan (use Annual Enrollment Period instead)
- Make changes to standalone Part D plans if you're on Original Medicare
- Make multiple changes (you get one change only during this period)
When Will My Coverage Start?
Changes take effect the first day of the month after your plan receives your enrollment request.
Special Enrollment Periods
Life doesn't always follow Medicare's calendar. Special Enrollment Periods allow you to enroll in or change your Medicare coverage outside the standard enrollment periods when you experience certain qualifying life events.
There are more than 20 different Special Enrollment Periods, each triggered by specific circumstances. The length of your SEP and when your coverage begins depends on which qualifying event applies to you.
Common Special Enrollment Period Situations
I am moving and have a Medicare Advantage or Prescription Drug plan.
If you move out of your plan's service area, you qualify for a Special Enrollment Period to choose a new plan.
Timeframe depends on when you notify your plan:
- Before moving: Your SEP runs from the month before your move through 2 months after
- After moving: Your SEP begins when you notify your plan and lasts 2 full months
💡 Tip: Even if you stay within your plan's service area but move to an area with different plan options, you may still qualify for this SEP.
I moved back to the United States after living outside the country.
Once you return to the U.S., your Medicare Parts A and B coverage should be reinstated. You can then enroll in a Medicare Advantage or Part D plan.
SEP Timeframe: Begins the month you move back to the U.S. and continues for 2 more months.
I am moving into, currently live in, or am moving out of an institution (such as a nursing home).
You can enroll in a new Medicare Advantage or Part D plan. Your enrollment period ends 2 months after you move out of the institution.
Coverage Start Date: The first day of the month after you complete your enrollment application.
I am discontinuing or losing employer sponsored coverage.
If you voluntarily discontinue or lose employer group coverage, you can enroll in a Medicare Advantage or Part D plan anytime while you still have employer coverage or within 2 months after you receive notice or after your coverage ends (whichever is later).
Coverage Start Date: If you apply before your employer coverage ends, your Medicare Advantage plan usually starts the first day of the month after your employer coverage ends.If you apply after your employer coverage ends, your plan typically starts the first day of the month after you enroll.
I have been notified that my employer-sponsored drug coverage is no longer creditable.
Non-creditable coverage means your employer plan doesn't provide prescription drug coverage as good as Medicare Part D. You can enroll in a Medicare Advantage or Part D plan.
SEP Timeframe: Begins when you're notified and ends 2 calendar months after notification or when creditable status ends (whichever is later).
⚠️ Important: If your employer failed to inform you about non-creditable coverage, or you learned about it after the fact, you may still qualify for a Special Enrollment Period. Contact Medicare at 1-800-MEDICARE for guidance.
🗒️ Important 2025 Update: Starting January 1, 2025, Medicare has expanded enrollment flexibility for people with both Medicare and Medicaid (dual-eligible) and those with Low-Income Subsidy (LIS) assistance.
I am dually eligible for Medicare and Medicaid.
Allows full-benefit and partial-benefit dual eligibles (and LIS-only) to switch between standalone PDPs or move from a Medicare Advantage plan to Original Medicare + a PDP once per month.
New Monthly “Integrated Care SEP”: Specifically for full-benefit duals to move into or switch between Fully Integrated Dual Eligible (FIDE) or Highly Integrated Dual Eligible (HIDE) Special Needs Plans (D-SNPs) on a monthly basis.
I am enrolled in Medicaid, and my level of assistance is changing.
Whether you qualify for more or fewer Medicaid benefits, you can adjust your Medicare coverage accordingly.
SEP Timeframe: Within 3 months of the change or notification of change (whichever is later).
Coverage Start Date: The month after you complete your enrollment application.
I am enrolled in Medicaid, but I am losing my Medicaid coverage.
You can enroll in a Medicare Advantage or Part D plan if you're losing Medicaid.
SEP Timeframe: Within 3 months of losing coverage or receiving notification (whichever is later).
Coverage Start Date: The month after you complete enrollment.
I have a Dual-Eligible Special Needs Plan (D-SNP) and I am losing eligibility.
If you no longer qualify for your D-SNP, you can switch to a different Medicare Advantage or Part D plan.
SEP Timeframe: Starts when you're notified until 3 months after your D-SNP coverage ends.
Coverage Start Date: The month after you complete enrollment.
I get Extra Help paying for my Medicare Part D prescription drug coverage.
If you qualify for Extra Help (also called the Low-Income Subsidy or LIS), you have ongoing flexibility to switch from a Medicare Advantage plan to Original Medicare and add a PDP, or switch PDP plans.
SEP Timeframe: Continuous (lasts as long as you have Extra Help).
2025 Update: Extra Help recipients can now make these monthly plan changes for greater flexibility throughout the year.
The Extra Help I receive is changing.
If your Extra Help level changes (more or less assistance), you can adjust your coverage.
SEP Timeframe: Within 3 months of losing Extra Help or receiving notification (whichever is later).
I am losing or gaining Extra Help for my Medicare Part D coverage.
If you no longer qualify or newly qualify for Extra Help, you can switch plans to find coverage that better fits your new cost-sharing situation.
SEP Timeframe: Within 3 months of losing Extra Help or receiving notification (whichever is later).
I belong to a State Pharmaceutical Assistance Program (SPAP).
State programs that help with prescription costs provide an annual opportunity to enroll in Medicare coverage with prescription drug benefits.
SEP Frequency: One Special Enrollment Period per calendar year.
Coverage Start Date: The month after you complete enrollment.
General Enrollment Period
January 1st to March 31st each yearMissed your Initial Enrollment Period? The General Enrollment Period gives you another chance to sign up for Medicare Part A and Medicare Part B coverage each year.
What You Can Do During GEP
- Enroll in Medicare Part A if you don't have it
- Enroll in Medicare Part B if you declined it during your Initial Enrollment Period
- If you enroll in Part A and/or Part B during GEP, you may qualify for a Special Enrollment Period for Part D. During this SEP, you can join a standalone Part D plan or a Medicare Advantage plan with drug coverage.
When Will My Coverage Start?
Typically coverage begins on the first day of the month following enrollment. Important considerations:
- Late enrollment penalties for Part B may apply and last for as long as you have Medicare.
- The penalty increases by 10% for each full 12-month period you could have had Part B but didn't sign up.
- Late enrollment penalties for Part A may apply If you do not qualify for premium-free Part A.
- The penalty is a 10% increase in premium for twice the number of years you delayed enrollment after first eligible.
- You receive a Part D Special Enrollment Period beginning the date you submit your application for premium Part A or Part B lasting for the first two months of enrollment in premium Part A or Part B. Coverage begins the first day of the month following the month you enroll in Part D.
- A Part D late enrollment penalty may apply if you have a 63+ day gap in creditable coverage since first eligible. The penalty is a permanent, 1% monthly addition (based off of the “national base beneficiary premium”) to your premium for each month you went without Part D or had creditable drug coverage.
Medigap Open Enrollment Period
- Starts the first day of the month you are both age 65 or older and enrolled in Medicare Part B, and lasts for 6 months.
- Guaranteed acceptance: insurers cannot deny you coverage or charge you more due to pre-existing health conditions during this time.
- You can apply at any time after your OEP, but in most states, insurers can use medical underwriting, deny coverage, or charge higher premiums based on your health history.
- Specific life events (e.g., losing employer-sponsored coverage, switching from a Medicare Advantage plan within the first year) may grant you a temporary window to buy a Medigap plan without medical underwriting.
Need Help Determining Your Enrollment Period?
We understand that Medicare enrollment periods can be confusing, especially when you're trying to figure out which one applies to your specific situation. Our team is here to help you understand your options and make the best decision for your healthcare needs.
Medicare Enrollment Period FAQs
Your current enrollment options depend on your situation:
- If you're turning 65 within three months or turned 65 within the past three months, you're in your Initial Enrollment Period and can enroll in any Medicare coverage.
- If you already have Medicare, you can make changes during the Annual Enrollment Period (from October 15th to December 7th) or Medicare Advantage Open Enrollment Period (from January 1st to March 31st, for MA members only).
- If you've experienced a qualifying life event like moving, losing employer coverage, or gaining Medicaid, you likely qualify for a Special Enrollment Period right now.
- If you missed your Initial Enrollment Period and don't have a qualifying event, you'll need to wait for the General Enrollment Period (from January 1st to March 31st) to enroll in Parts A and B, with coverage starting July 1st.
Deadlines vary significantly based on which enrollment period applies to you:
- Your Initial Enrollment Period ends three months after your 65th birthday month, and enrolling earlier in this window means earlier coverage.
- The Annual Enrollment Period always runs from October 15th through December 7th, with changes effective January 1st.
- Special Enrollment Periods typically last 2-3 months from your qualifying event, though some (like having Medicaid or Extra Help) may provide ongoing enrollment opportunities.
- If you're losing employer coverage triggers a Medicare Special Enrollment Period that typically lasts 8 months to enroll in Parts A and B, but only 2 months to join a Medicare Advantage or Part D plan without penalty.
Missing these deadlines can mean waiting months for another opportunity and potentially facing late enrollment penalties, so it's important to act promptly once you know which period applies to you.
The key to avoiding penalties is enrolling in Medicare Part B and Part D during your Initial Enrollment Period (the 7 months around your 65th birthday) unless you qualify for a penalty-free delay. You can delay Part B without penalty only if you have creditable coverage through current employment (yours or your spouse's); COBRA and retiree coverage don't count.
For Part D, you can delay enrollment without penalty only if you have creditable prescription drug coverage, which your employer or plan must certify in writing each year. If you do delay, you should enroll during your 2-month SEP window and not go without creditable coverage for over 63 days to avoid penalties.The Part B penalty is 10% of the premium for each 12-month period you could have had it but didn't, and it lasts as long as you have Part B.
The Part D penalty is 1% of the national base premium for each month you were without creditable coverage, and it also lasts for life.Missing an enrollment deadline can have significant consequences.
If you miss your Initial Enrollment Period for Part B and don't have employer coverage, you'll have to wait until the next General Enrollment Period (January 1st through March 31st) to enroll, with coverage starting the first day of the month after you enroll, and you'll face a lifetime late enrollment penalty of 10% per year you delayed.
If you miss enrolling in Part D during your Initial Enrollment Period without creditable drug coverage, you'll face a late enrollment penalty when you eventually enroll, calculated as 1% of the national base premium times the number of months you went without coverage.
For Medicare Advantage and Part D plan changes outside your enrollment period, you generally must wait until the next Annual Enrollment Period (October 15th through December 7th) unless you qualify for a Special Enrollment Period.
However, if you can demonstrate you missed a deadline due to a qualifying circumstance beyond your control (such as a natural disaster, serious illness, or receiving incorrect information from a government employee), you may be able to request an exception by calling 1-800-MEDICARE.
We hope this information has been helpful, but we also realize it can all be a bit overwhelming at times. You can always reach out to our team to discuss your specific situation; our contact information is below!