| Enrollment Period | Enrollment Dates | Who can enroll | Effective Date |
| AEP or Annual Enrollment Period | Oct. 15th to Dec. 7th | Medicare eligible | January 1st |
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| IEP or Initial Enrollment Period |
3 months before 65th birthday, month of birthday and 3 months after |
First eligible for Medicare | Month of birthday or Month following enrollment |
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| SEP or Special Enrollment Period | within 60 days of a triggering event | Beneficiaries who experience a trigger event | 1st of the month following enrollment |
| General Enrollment Period* | Jan. 1 to March 31st | MA or MA-PD beneficiaries | 1st of the month following enrollment |
*only for those enrolled on a Medicare Advantage plan