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ENROLLMENT WINDOWS AND TIMING

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Pay attention to your Medicare enrollment window. If you miss it, you might have to pay a penalty, pay more for coverage or have fewer choices.

  Initial
Enrollment—
When		 Initial
Enrollment —
How		 Late
Enrollment		 Making
Changes
Part A Anytime from three months before your 65th birthday to three months after the month of your 65th birthday. Automatic, if you're already receiving Social Security benefits. Otherwise, enroll at your Social Security Office. There are no penalties for signing up late, unless you pay a monthly premium for Part A. Renews each year automatically.
Part B Same as Part A. Automatic, if you're receiving Social Security benefits when you turn 65 or otherwise become eligible for Medicare. If you're not receiving Social Security benefits, sign up at your Social Security office. You can also refuse coverage at this office. If you enroll after the initial enrollment period, premiums will be higher unless you qualify for an exception. Renews each year automatically.
Part C (Medicare Advantage) Anytime from three months before your 65th birthday to three months after the month of your 65th birthday. Enroll through a private insurance company. If you miss the enrollment window, you must wait to join a plan between November 15 and December 31 of each year unless you qualify for an exception. You can change your plan during open enrollment, from January 1 through March 31 each year. If you have a Medicare Advantage plan with built-in drug coverage, you can only change to another plan with drug coverage. You cannot add or drop your drug coverage during this time.
Medicare Part D (prescription drug coverage) Anytime from three months before your 65th birthday to three months after the month of your 65th birthday. Enroll through a private insurance company. If you miss the enrollment window, you must wait to join between November 15 and December 31 of each year, unless you qualify for an exception. During the Annual Election Period of November 15 to December 31, you can add, drop or change your Part D coverage. This is the only time of year you can do this, unless you qualify for an exception.
Medicare Supplement Insurance When you turn 65 and enroll in Medicare Part B, you have a guaranteed right to buy a Medicare Supplement policy for six months. You buy Medicare Supplement Insurance through a private insurance company. If you miss the enrollment window you can apply at any time. But you may pay a higher rate or be rejected if you have a history of health problems. You can add or drop at any time. If you change policies, it's best to wait until the new policy is effective before dropping the old policy.