Many individuals are automatically enrolled in Original Medicare coverage and receive their red, white, and blue Medicare card in the mail three months before their month of eligibility. However, some may need to manually enroll in this coverage. Usually the best time to enroll in Original Medicare is during the Medicare Initial Enrollment Period. During this time, beneficiaries may opt to enroll in Original Medicare, Medicare Advantage (Part C), or Medicare Part D prescription drug coverage.

The Initial Enrollment Period (IEP) differs for each beneficiary. Generally, this seven month period:

  • Begins three months before the beneficiary’s month of eligibility
  • Includes the eligibility month
  • Lasts for three months following the eligibility month.

The eligibility month is defined as either the month that an individual turns age 65 or their 25th month of receiving Social Security Disability Insurance (SSDI) or certain disability benefits from the Railroad Retirement Board.

 Initial Enrollment in Part A and Part B

Those who are not automatically enrolled in Original Medicare, must enroll in Part A and Part B through the Social Security Administration (SSA).

The effective date of your coverage depends on when you enroll during your Initial Enrollment Period (IEP). If you enroll during the first three months of your Initial Enrollment Period, then your benefits will begin on the first day of the 4th month of your IEP, also known as your month of eligibility—that coincides with your birthdate month if you are turning 65 years old or the 25th month you receive disability benefits if you are younger than 65 and eligible for Medicare benefits because of a disability condition. If you enroll during your eligibility month or in the three months afterwards, then your benefits begin on the first day of the month following your enrollment. The later you enroll in Original Medicare, the later your coverage begins. You will want to be careful not to postpone your enrollment until the last minute because your coverage is not effective immediately upon enrollment.  If you inadvertently delay enrollment in Part B until after your Initial Enrollment Period, you may be subject to a late enrollment penalty.

Initial Enrollment in Medicare Advantage (Part C) and Prescription Drug Coverage (Part D)

Individuals may choose to receive their Medicare benefits from private insurance companies who contract with Medicare.  A Medicare Advantage plan must provide at least the same benefits as Original Medicare Part A and Part B (except for hospice care which continues to be covered under Part A). Many Medicare Advantage plans also offer extra benefits.  If one of these extra benefits is Medicare prescription drug coverage, the plan is called a Medicare Advantage Prescription Drug Plan.  By enrolling in a Medicare Advantage Prescription Drug Plan, you receive your health and prescription drug coverage from a single plan. To be eligible to enroll in these types of Medicare Advantage plans, you must be enrolled in both Part A and Part B.  You can enroll in a Medicare Advantage plan:

  • During the Initial Enrollment Period, that is the seven-month period when you first become eligible for Medicare either due to a disability or turning age 65; or
  • From April 1 to June 30 if you were already enrolled in Part A and enrolled in Part B during the General Enrollment Period

You have another choice for your Medicare prescription drug coverage:  you may be able to enroll in a stand-alone Medicare Part D Prescription Drug Plan offered by a Medicare-approved private insurance company.  Medicare prescription drug coverage is available to beneficiaries who are enrolled in either Medicare Part A and/or Part B.  You can enroll in a stand-alone Medicare Part D Prescription Drug Plan during the same time frames as described above for enrollment in Medicare Advantage plans.

Beneficiaries who delay enrollment in Medicare, including those who are still working, may be able to enroll in a Medicare Advantage plan or a stand-alone Medicare Part D Prescription Drug Plan at a later date as a result of a Special Enrollment Period or during the Annual Election Period (also called the Fall Open Enrollment Period) when Medicare beneficiaries may make changes to their Medicare coverage.