Medicare enrollment periods, explained

Medicare has a handful of sign-up windows. Missing one can mean waiting months for coverage or paying a penalty, so it helps to know which applies to you.

Initial Enrollment Period

Your first chance to sign up for Part A and Part B: 7 months around your 65th birthday (3 months before, your birthday month, 3 months after).

Open Enrollment: October 15 to December 7

Once a year, anyone with Medicare can switch between Original Medicare and Medicare Advantage, change Medicare Advantage plans, or join, switch or drop a Part D drug plan. Changes start January 1.

Medicare Advantage Open Enrollment: January 1 to March 31

If you're already in a Medicare Advantage plan, you can switch to a different one or go back to Original Medicare (and join a drug plan) once during this window. Changes start the first of the next month. It can't be used to move from Original Medicare into Medicare Advantage.

General Enrollment Period: January 1 to March 31

If you missed your Initial Enrollment Period and don't qualify for a Special Enrollment Period, you can sign up for Part A or Part B now. Coverage starts the first of the month after you sign up, and a late penalty may apply.

Special Enrollment Periods

Certain life events open a window outside the usual dates, for example losing employer coverage, moving out of your plan's area, or qualifying for Medicaid or Extra Help. How long you have depends on the event.

Medigap Open Enrollment

A one-time, 6-month window starting the month you're 65 or older and enrolled in Part B. It's the only time in most states when insurers must sell you any Medigap policy they offer without looking at your health.