Annual Enrollment Periods
Most people can only change their Medicare and Marketplace coverage during specific yearly windows. Missing a deadline can lock you in until the next open season, though life events may create exceptions.
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October 15 – December 7
Medicare Open Enrollment (Annual Election Period)
The main yearly window for anyone with Medicare Parts A, B, or D. Switch from Original Medicare to Medicare Advantage, between MA plans, change your Part D drug plan, or switch to/from Medigap. Changes take effect January 1. This is the most important deadline for existing Medicare members.
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January 1 – March 31
Medicare Advantage Open Enrollment Period
If you're already in a Medicare Advantage plan, you can switch to a different MA plan, return to Original Medicare, or drop coverage during this window. This gives a second chance to change MA plans if you were unhappy with your choice in the fall.
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January 1 – March 31
Medicare General Enrollment Period
For those who missed their Initial Enrollment Period or didn't sign up for Part A or Part B when they first became eligible. Enroll during this window, though you may face a permanent late penalty for delayed enrollment.
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3 months before – 3 months after your 65th birthday
Initial Enrollment Period (IEP)
A 7-month window centered on your birth month when you first become eligible for Medicare. This is your penalty-free window to sign up for Part A, Part B, and Part D. Missing it can trigger lifetime penalties. Learn more at Turning 65.
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Date varies yearly (typically November–January)
Health Insurance Marketplace Open Enrollment Period
For ACA Marketplace plans on healthcare.gov or state exchanges. Exact dates are announced annually—check healthcare.gov each fall. Outside this window, you need a qualifying life event to enroll.
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Year-round
Medicaid & CHIP Continuous Enrollment
Medicaid and the Children's Health Insurance Program (CHIP) accept applications anytime. Eligibility rules and enrollment processes vary significantly by state. Visit State Directory for your state's program.
Special Enrollment Periods (SEPs)
If you experience a qualifying life event—such as losing employer coverage, moving to a new state, getting married, having a child, or retiring—you may have a 60-day window to enroll in or change Medicare or Marketplace coverage outside the regular season. These are called Special Enrollment Periods (SEPs). The specific events that qualify, the timing, and the deadlines vary by program and plan. For details on life events affecting your coverage, see Retiring or Losing Coverage and Moving to Another State.
Quick Lookup: Which Window Do I Need?
| I want to… | Use this window | Timing |
|---|---|---|
| Change Medicare Advantage or Part D (I already have Medicare) | Medicare Open Enrollment (Annual Election Period) | Oct 15 – Dec 7 |
| Switch between MA plans (I'm already in MA) | MA Open Enrollment Period | Jan 1 – Mar 31 |
| Sign up for Medicare for the first time at 65 | Initial Enrollment Period (IEP) | 3 mo. before – 3 mo. after birthday month |
| Change my Marketplace health plan | Marketplace Open Enrollment | Announced yearly (typically Nov–Jan) |
| Apply for Medicaid or CHIP | Continuous enrollment (anytime) | Year-round |
| I just had a life event (moving, job loss, marriage, etc.) | Special Enrollment Period (SEP) | Usually 60 days from the event |
Important Reminders
- Statutory dates are stable. October 15 – December 7 and January 1 – March 31 are fixed by law. Marketplace dates vary each year—always verify at healthcare.gov.
- Medicaid rules differ by state. Some states have restricted enrollment periods; others allow year-round. Check your state's program at the State Directory.
- Late penalties stick. If you miss your Initial Enrollment Period and don't qualify for a Special Enrollment Period, you pay a permanent penalty for delayed enrollment for Part B and Part D—even if you enroll later.
- Life events matter. Losing health coverage, moving, marriage, divorce, and birth or adoption may trigger a Special Enrollment Period. See Enrollment & Deadlines for the full list of qualifying events.
- Keep records. Save your enrollment confirmations and plan details. If you or a family member enroll during a Special Enrollment Period, you'll need documentation of the qualifying event.
Next Steps
- For more detail on enrollment rules, timelines, and penalties, see Enrollment & Deadlines.
- If you are turning 65 soon, read Turning 65 for step-by-step guidance.
- If you have had a major life change, explore Retiring or Losing Coverage and Moving to Another State.
- To compare plan types and understand your choices, see Plan Types.