Medicare Enrollment – Navigating Medicare can feel like learning a second language. Between the alphabet of Parts A, B, and D and a series of firmly enforced deadlines, it’s easy to feel unsure about what applies and when.
Missing an enrollment window may cause delays or trigger long-term late-enrollment penalties. That’s why having a clear Medicare enrollment deadlines calendar is essential.
Below is a simple, step-by-step breakdown of the five Medicare enrollment windows you should know for 2026, along with a free digital calendar to keep on hand.
1. Your First Opportunity: Initial Enrollment Period
If you turn 65 in 2026, this is the most important enrollment window to understand.
When:
- A seven-month window that includes:
- Three months before your 65th birthday month
- Your birthday month
- Three months after your birthday month
Why it matters:
This is your first opportunity to enroll in Medicare Part A (hospital insurance) and Part B (medical insurance).
Why timing matters:
If you miss this window and don’t have other creditable coverage, late-enrollment penalties may apply and continue long term.
2. Annual Review Window: Annual Enrollment Period
Dates: October 15 – December 7
Each fall, people already enrolled in Medicare can review and adjust their selections for the coming year.
During this time, you can:
- Switch between Original Medicare and Medicare Advantage
- Change Medicare Advantage plans
- Change Part D prescription drug plans
Helpful reminder: Plans update costs annually. Reviewing your Annual Notice of Change (ANOC) helps avoid surprises early in the year.
3. Catch-Up Enrollment: General Enrollment Period
Dates: January 1 – March 31
This period is designed for individuals who did not enroll in Medicare Part B when first eligible.
Who it applies to:
Anyone who missed their Initial Enrollment Period and does not qualify for a Special Enrollment Period.
When benefits begin:
Coverage typically starts the month after enrollment is completed.
4. Medicare Advantage Open Enrollment Period
Dates: January 1 – March 31
This window applies only to individuals already enrolled in a Medicare Advantage plan.
You may:
- Switch to a different Medicare Advantage plan, or
- Return to Original Medicare
Only one change is allowed during this period.
5. Special Enrollment Period: When Life Changes
Certain life events may allow enrollment outside standard windows, including:
- Leaving employer coverage: An eight-month window typically applies
- Moving: Especially if your plan isn’t available in your new location
- Changes in Medicaid eligibility
Each situation has specific timing rules, so accurate documentation is crucial.
Never Miss a Deadline: Download the 2026 Medicare Enrollment Calendar
Keeping track of Medicare deadlines can feel overwhelming, but it doesn’t have to be.
at WeShare we’ve created a free 2026 Medicare enrollment calendar that you can add directly to your phone or computer.
Download the 2026 Medicare Enrollment Calendar here.
