Medicare Enrollment Periods: Key 2026 Dates
Understanding when you can enroll in Medicare, and when you can make changes, is one of the most important parts of managing your coverage. Missing a window can mean waiting months for another opportunity, and in some cases paying a lifelong late penalty.
Your Initial Enrollment Period (IEP)
When you first become eligible for Medicare, you get a seven-month window to sign up. It begins three months before the month you turn 65, includes your birthday month, and continues for three months afterward. For most people, enrolling during this period helps avoid delays and late penalties.
Fall Open Enrollment (October 15 – December 7)
Each fall, anyone with Medicare can review and change their coverage. During this window you can switch between Original Medicare and a Medicare Advantage plan, change Medicare Advantage plans, or join, drop, or switch a Part D prescription drug plan.
Any changes you make take effect January 1 of the following year, provided the plan receives your enrollment request by December 7. Because plans can adjust their costs and covered drugs annually, this is a good time to review your options even if you’re satisfied with your current coverage.
Medicare Advantage Open Enrollment (January 1 – March 31)
If you’re already enrolled in a Medicare Advantage plan at the start of the year, you have one opportunity during this window to switch to a different Medicare Advantage plan or return to Original Medicare (and join a Part D plan if needed).
You cannot use this period to move from Original Medicare into a Medicare Advantage plan, and you cannot use it to join or switch a standalone Part D plan if you’re on Original Medicare.
There’s a second version of this period that’s easy to miss. If you’re new to Medicare and enrolled in a Medicare Advantage plan, you get your own Medicare Advantage Open Enrollment Period running from the first month you have both Part A and Part B through the last day of the third month you have both. This one isn’t tied to the calendar — it can fall anywhere in the year, and it’s available even though you weren’t in a plan on January 1.
General Enrollment Period (January 1 – March 31)
If you missed your Initial Enrollment Period and don’t qualify for a Special Enrollment Period, this is when you can sign up for Part A and/or Part B. Coverage starts the month after you sign up.
This period shares its dates with Medicare Advantage Open Enrollment, which is a common source of confusion — they’re different periods doing different things. The General Enrollment Period is for getting into Medicare; the Medicare Advantage period is for changing plans you already have.
Special Enrollment Periods (SEPs)
Certain life events — moving, losing other coverage, or qualifying for assistance programs — can open a Special Enrollment Period that lets you make changes outside the standard windows.
How long you get depends entirely on which event triggered it. Two months is common, but it is not a safe default:
| Situation | Window |
|---|---|
| Most plan changes (moving, losing coverage) | About 2 months |
| Losing Medicaid or Extra Help eligibility | 3 full months |
| Part B after employer coverage ends | 8 months |
| First-time Medicare Advantage enrollee at 65 (trial right) | 12 months |
| Dual eligible or receiving Extra Help | Once per calendar month, ongoing |
| Joining a 5-star plan | December 8 – November 30 |
| Chronic-condition SNP, PACE, or a low-performing plan | Open-ended |
Two of these matter more than the rest. If you have Medicaid or Extra Help, you generally get a monthly opportunity to change drug plans rather than a one-time window. And if you’re leaving employer coverage, the Part B Special Enrollment Period runs eight months — assuming it’s two would cost you a lifetime penalty.
Keeping these dates in mind can help you avoid gaps in coverage and unnecessary penalties. If you’re unsure which period applies to your situation, it’s worth reviewing your options well before a deadline arrives.
Sources: Medicare.gov; CMS Product No. 11219, “Understanding Medicare Advantage and Medicare Drug Plan Enrollment Periods” (March 2026).
We do not offer every plan available in your area. Any information we provide is limited to those plans we do offer in your area. Please contact Medicare.gov or 1-800-MEDICARE to get information on all of your options.
This content is for general educational purposes and is not a complete description of benefits. Contact the plan for more information. Medicare Compare Agency, 2201 Providence Park, #150, Birmingham, Alabama 35242.