The Medicare Initial Enrollment Period is the first time most beneficiaries will enroll in Original Medicare. Unless you are receiving benefits through Social Security or the Railroad Retirement Board when you turn 65, you will need to self-enroll during this window that is unique to you.

Medicare Initial Enrollment Period

Your Medicare Initial Enrollment Period starts on the first day of the month, three months before you turn 65 and ends on the last day of the third months after the your 65th birth month. Unless you originally became eligible for Medicare due to disability, your Initial Enrollment Period only happens once in a lifetime for most beneficiaries. Therefore, it is essential to understand how the enrollment period works to avoid late enrollment penalties in the future.

It is recommended to begin the enrollment process early in your Initial Enrollment Period because applications can take up to four weeks to be approved. Once you enroll, your Medicare Part A and Part B benefits will begin on the first day of your 65th birth month. If you enroll after the first day of your 65th birth month, Medicare benefits will not start until the first of the following month.

Delaying Medicare Initial Enrollment

You may delay enrolling in Original Medicare, but to avoid the penalty in the future, you must ensure you have creditable coverage in place. The most common reason people delay signing up for Medicare past their Initial Enrollment Period is that they have turned 65 and are still employed and using group health benefits.

If this is the case, you can keep your group health benefits until you decide to retire. At this time, you will receive a Special Enrollment Period to enroll in Original Medicare without penalty.

Automatic Medicare Enrollment

To qualify for automatic enrollment in Medicare Part A and Part B at 65, you must be enrolled in a Railroad Retiree Board program or collecting Social Security. When you’re under 65, you’ll automatically enroll if you collect Social Security Disability Income (SSDI) benefits for at least 24 months or receive a diagnosis of amyotrophic lateral sclerosis (ALS).

  • If any of the above applies to you, you should receive your red, white, and blue Medicare card in the mail approximately three months before your 65th birthday or, if under 65, up to four weeks after you become Medicare-eligible.
  • If none of the above applies to you, you must contact your local Social Security office up to three months before your 65th birthday to enroll yourself in Original Medicare.
  • Those who are under 65 and eligible for Medicare due to end-stage renal disease (ESRD) must also self-enroll and will receive their I.D. card within four weeks of eligibility.

When Does Medicare Part A and Part B Coverage Begin

The date your Medicare Part A and Part B coverage begins depends on the date you enroll. If you enroll during the three months prior to your 65th birthday, your Medicare benefits will begin on the first day of your 65th birth month. If you enroll during the month of your 65th birthday or any of the three months following your birthday, your coverage will start on the first day of the following month.

Medicare Part A and Part B Effective Dates Rely on When You Enroll in Coverage

Enrolled On:Coverage Start:
The 3 months before your 65th birthdayThe 1st day of your birthday month
The month of your 65th birthday1 month after your birthday
The 1st month after your birthday3 months after your birthday
The 2nd month after your birthday5 months after your birthday
The 3rd month after your birthday6 months after your birthday

Medicare Part D Initial Enrollment Period

The Medicare Part D Initial Enrollment Period is the same as the enrollment period for Medicare Part A and Part B. If you do not enroll in a Medicare Part D plan during this time and lack creditable coverage, you will need to wait until the next Annual Enrollment Period to apply for Part D coverage.

Suppose you delay your Medicare Part D enrollment without creditable coverage. In this case, you will be subject to an enrollment penalty added to your monthly premium each month you have a Medicare Part D plan.

How to Apply for Medicare Using Your Initial Enrollment Period

Applying for Medicare using your Initial Enrollment period is simple. During this window, you can apply online at the Social Security website, over the phone, or in person at your local Social Security office.

Your Medicare Initial Enrollment Period

Sources:

  1. Creditable Coverage, Centers for Medicare & Medicaid Services. Accessed February 2022.
    https://www.cms.gov/Medicare/Prescription-Drug-Coverage/CreditableCoverage
  2. Top 5 Things You Need to Know About Medicare Enrollment, Centers for Medicare & Medicaid Services. Accessed February 2022.
    https://www.cms.gov/Outreach-and-Education/Find-Your-Provider-Type/Employers-and-Unions/Top-5-things-you-need-to-know-about-Medicare-Enrollment
  3. When Does Medicare Coverage Start?, Medicare.gov. Accessed February 2022.
    https://www.medicare.gov/basics/get-started-with-medicare/sign-up/when-does-medicare-coverage-start

Jagger Esch

Medicare Expert

Jagger Esch is the Medicare expert for MedicareFAQ and the founder, president, and CEO of Elite Insurance Partners and MedicareFAQ.com. Since the inception of his first company in 2012, he has been dedicated to helping those eligible for Medicare by providing them with resources to educate themselves on all their Medicare options. He is featured in many publications as well as writes regularly for other expert columns regarding Medicare.