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The Medicare Enrollment Calendar

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Sep
Oct
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Dec
MA OEP & GEP · Jan 1 to Mar 31
AEP · Oct 15 to Dec 7
SEPs · any time a qualifying event occurs

IEP, Initial Enrollment Period

7 months around the 65th birthday

The 3 months before the birthday month, the birthday month, and the 3 months after. A person's first chance to enroll in Medicare.

Enrolling before the birthday month means coverage can start the first of the birthday month.

AEP, Annual Election Period

October 15 to December 7

Anyone on Medicare can join, switch, or drop an Advantage or Part D plan. Changes take effect January 1.

Your busiest selling season. The last election made before Dec 7 is the one that sticks.

MA OEP, Advantage Open Enrollment

January 1 to March 31

Someone already in a Medicare Advantage plan may make one switch to another MA plan or back to Original Medicare (with Part D).

For people already in MA only. Not a window to leave Original Medicare.

GEP, General Enrollment Period

January 1 to March 31

For people who missed their IEP and do not qualify for an SEP. They can enroll in Part A and B here.

Late enrollment penalties may apply. Coverage begins the month after enrollment.

SEPs, Special Enrollment Periods

Triggered by a qualifying life event, any time of year

Events like moving out of a plan's service area, losing employer or other creditable coverage, or qualifying for Extra Help open a window to make a change outside the standard periods. Each SEP has its own rules and length.

Always confirm the specific SEP and its deadline for the client's situation.

Medigap, its own clock

One-time, 6-month Medigap Open Enrollment

The Medigap Open Enrollment Period is a one-time, 6-month window that begins when the client is 65 or older and enrolled in Part B. During it, they have guaranteed-issue rights with no medical underwriting.

North Carolina has no annual birthday rule. After that one window closes, switching a Medigap plan in NC generally requires medical underwriting, unless a federal guaranteed-issue right applies.

Training aid, not legal or enrollment advice. Dates and rules can change year to year. Confirm current periods, SEP eligibility, and the client's specific situation against Medicare.gov and your carrier guidance before advising. Last reviewed June 2026.
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