Medicare Initial Enrollment Period (IEP) is centered around your birth month. Beginning three months before and expanding for three months after your birth month of your 65th birthday, you will have seven these months to enroll in Medicare.
Delaying your Social Security retirement benefits or Railroad Retirement Benefits (RRB) beyond age 65 is a common practice. Doing so places the responsibility on your shoulders to sign up for Medicare Part A and/or Part B during your IEP.
If you are not eligible for retirement benefits from Social Security or the RRB, you will not be automatically enrolled into Original Medicare. This does not prevent you from signing up for Medicare Part A and/or Part B during your IEP. You may not be able to get premium-free Medicare Part A, and the cost of your monthly Part A premium will depend on how long you worked and paid Medicare taxes. You will still have to pay a Medicare Part B premium.
A General Enrollment Period is available if you did not enroll during the IEP when you were first eligible. The general enrollment period for Original Medicare is from January 1 through March 31 of each year. Keep in mind that you may have to pay a late enrollment penalty for Medicare Part A and/or Part B if you did not sign up when you were first eligible.
Many individuals choose not to enroll in Part B when they first were eligible in their IEP because they had group coverage from an employer that covered medical insurance. If you lose your group insurance, or if you decide you want to switch from your group coverage to Medicare, you can sign up at any time that you are still covered by the group plan or during a Special Enrollment Period(SEP).
There is an eight-month special enrollment period which begins either the month that your employment ends or when your group health coverage ends, whichever occurs first. If you enroll during an SEP, you generally do not have to pay a late enrollment penalty.
The Special Enrollment Period does not apply if you are eligible for Medicare because you have ESRD. Please also keep in mind that COBRA and retiree health coverage are not considered current employer coverage and would not qualify you for a special enrollment period.