Don't Miss Your Window
Medicare Enrollment Deadlines, Explained.
Missing an enrollment deadline can mean months without coverage — or a permanent late-enrollment penalty. Here's every window you need to know, and exactly when it applies to you.
Important: Enrollment windows are time-sensitive. Missing a deadline can result in a permanent premium penalty or a gap in coverage.
Calendar Overview
The Year at a Glance
Key Medicare dates plotted across the calendar year.
Initial Enrollment Period
The Initial Enrollment Period is your first opportunity to sign up for Medicare Parts A and B. It's a 7-month window centered on your 65th birthday. Enrolling on time avoids late penalties and ensures seamless coverage.
Who This Applies To
Anyone approaching age 65 who is not already receiving Social Security benefits or covered by qualifying employer insurance.
If you're still covered by employer insurance at 65, you may be able to delay Part B without penalty — but verify with your HR department first.
Key Dates & Details
Window opens
3 months before your 65th birthday month
Coverage starts
The month you turn 65 (if enrolled in months 1–3)
Window closes
3 months after your 65th birthday month
Late penalty risk
10% per year for Part B if you miss IEP without qualifying coverage
Annual Election Period
The Annual Election Period — also called Open Enrollment — is the one time each year when any Medicare beneficiary can make changes to their coverage. You can switch from Original Medicare to Medicare Advantage, change your Part D drug plan, or switch between Advantage plans.
Who This Applies To
All Medicare beneficiaries. This is the most widely used enrollment window and applies to everyone, every year.
Even if you're happy with your current plan, review it every AEP. Premiums, formularies, and networks change annually — your plan may no longer be the best fit.
Key Dates & Details
AEP opens
October 15 (every year)
AEP closes
December 7 (every year)
Changes take effect
January 1 of the following year
Who can use it
Any Medicare beneficiary — no qualifying event required
Special Enrollment Period
A Special Enrollment Period is triggered by specific life events that allow you to make Medicare changes outside of the standard enrollment windows. Common triggers include losing employer coverage, moving to a new service area, or qualifying for Extra Help (Low Income Subsidy).
Who This Applies To
Medicare beneficiaries who experience a qualifying life event such as job loss, relocation, or a change in Medicaid eligibility.
Don't wait until the last day of your SEP window. Processing can take time, and you want coverage to start without a gap.
Key Dates & Details
Losing employer coverage
8-month SEP for Part B; 63-day SEP for Part D
Moving out of plan's service area
60-day SEP from date of move
Qualifying for Medicaid or Extra Help
Monthly SEP — enroll any time
Plan loses Medicare contract
60-day SEP from notice date
General Enrollment Period
The General Enrollment Period is for people who missed their Initial Enrollment Period and don't qualify for a Special Enrollment Period. It runs every year from January through March, but coverage doesn't begin until July — and a late-enrollment penalty is typically assessed.
Who This Applies To
People who missed their IEP and do not qualify for a Special Enrollment Period. The GEP is a last resort — the late penalty is permanent.
The Part B late-enrollment penalty is permanent and compounds over time. If you're approaching 65, enroll during your IEP to avoid it entirely.
Key Dates & Details
GEP opens
January 1 (every year)
GEP closes
March 31 (every year)
Coverage begins
July 1 of the same year
Late penalty
10% added to Part B premium for each full 12-month period you were eligible but not enrolled
Not Sure Which Window Applies to You?
Every situation is different. A licensed agent can identify your exact enrollment window and make sure you don't miss it.