Rachel Christian, writer and researcher for RetireGuide
  • Written by
    Rachel Christian

    Rachel Christian

    Financial Writer and Certified Educator in Personal Finance

    Rachel Christian is a writer and researcher for RetireGuide. She covers annuities, Medicare, life insurance and other important retirement topics. Rachel is a member of the Association for Financial Counseling & Planning Education.

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  • Edited By
    Matt Mauney
    Matt Mauney, Senior Editor for RetireGuide

    Matt Mauney

    Financial Editor

    Matt Mauney is an award-winning journalist, editor, writer and content strategist with more than 15 years of professional experience working for nationally recognized newspapers and digital brands. He has contributed content for ChicagoTribune.com, LATimes.com, The Hill and the American Cancer Society, and he was part of the Orlando Sentinel digital staff that was named a Pulitzer Prize finalist in 2017.

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  • Reviewed By
    Aflak Chowdhury
    Aflak Chowdhury

    Aflak Chowdhury

    Medicare Expert

    Aflak Chowdhury is a Medicare expert and independent insurance broker specializing in group health insurance. He has worked for major providers including Humana and Principal Financial Group and today works mainly in the small group market.

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  • Published: July 24, 2020
  • Updated: May 8, 2023
  • 4 min read time
  • This page features 6 Cited Research Articles
Fact Checked
Fact Checked

A licensed insurance professional reviewed this page for accuracy and compliance with the CMS Medicare Communications and Marketing Guidelines (MCMGs) and Medicare Advantage (MA/MAPD) and/or Medicare Prescription Drug Plans (PDP) carriers’ guidelines.

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How to Cite RetireGuide.com's Article

APA Christian, R. (2023, May 8). Medicare Initial Enrollment Period. RetireGuide.com. Retrieved June 21, 2024, from https://www.retireguide.com/medicare/eligibility-and-enrollment/initial-enrollment-period/

MLA Christian, Rachel. "Medicare Initial Enrollment Period." RetireGuide.com, 8 May 2023, https://www.retireguide.com/medicare/eligibility-and-enrollment/initial-enrollment-period/.

Chicago Christian, Rachel. "Medicare Initial Enrollment Period." RetireGuide.com. Last modified May 8, 2023. https://www.retireguide.com/medicare/eligibility-and-enrollment/initial-enrollment-period/.

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What Is the Initial Enrollment Period for Medicare?

The initial enrollment period is the first time you are eligible to sign up for Medicare.

You can join Medicare Part A and Part B during this time, or select a Medicare Advantage (Part C) plan.

The Medicare initial enrollment period lasts seven months and it:
  • Begins three months before your birthday month.
  • Includes the month you turn 65.
  • Ends three months after your birthday month.

Social Security will mail you sign-up instructions when your initial enrollment period begins. You must enroll in Medicare through the Social Security Administration.

After enrolling, you will receive your Medicare benefits through the U.S. Centers for Medicare and Medicaid Services.

If you already receive Social Security benefits, the Social Security Administration will automatically enroll you at age 65 for Original Medicare (Part A and Part B).

After your initial enrollment period, there are specific times each year when you can change Medicare plans, known as open enrollment periods.

When Does Medicare Coverage Begin?

The start of your Original Medicare coverage depends on when you sign up during the initial enrollment period.

2023 Rules: When Does Medicare Part A and Part B Coverage Begin?
If You Sign UpCoverage Begins (In Most Cases)
Three months before your 65th birthdayThe first day of your birthday month
During your birthday monthThe first day of the month after your birthday month
The month after your birthdayThe first day of the month after you sign up
Two months after your birth monthThe first day of the month after you sign up
Three months after your birth monthThe first day of the month after you sign up

Keep in mind that if you miss your initial enrollment period and try to sign up for Medicare later, your coverage may be delayed and cost more money.

However, if you’re still working at 65 and have health insurance through your employer, you may be able to delay Medicare enrollment without this penalty.

Have you selected your 2024 Medicare plan?
Maximize your Medicare savings by connecting with a licensed insurance agent. Annual Enrollment is open until December 7th.

When Can You Sign Up for Medicare Advantage or Part D?

If you want to enroll in a Medicare Advantage plan (Part C) — an alternative to Original Medicare that is administered by private companies — you must sign up on your own.

The same applies to Medicare Part D prescription drug coverage.

When You Can Sign Up for Medicare Advantage or Part D
You’re Turning 65
You can enroll during the seven-month window that begins three months before you turn 65, includes your birth month and extends three months after that. If you sign up for a Medicare Advantage plan during this time, you can drop it at any point during the following 12 months and return to Original Medicare.
You Have a Disability and Are Under 65
Your Medicare coverage begins 24 months after you first start receiving Social Security disability benefits or Railroad Retirement Board disability benefits. Your sign-up time extends through the 28th month after you first begin receiving disability benefits.
You Have a Disability and You Turn 65
During this time, you can sign up for a Medicare Advantage or Part D plan. If you already have a Part C or Part D plan, you can switch to a different one. You have a seven-month period to do so. It begins three months before you turn 65, includes your birth month and extends three months after that.

Enrollment in a Medicare Supplement Plan

There are different rules for enrolling in a supplemental insurance plan, also known as Medigap.

According to Centers for Medicare & Medicaid Services, the best time to buy a Medigap policy is the first six months after the month you turn 65.

For example, if you turn 65 in June and enroll in Part B the same month, you should buy a Medigap policy between June and November.

You must be enrolled in Medicare Part B to sign up for a Medigap policy.

John Clark, licensed insurance advisor and owner of Senior Solutions Insurance Agency, explains why you should sign up for a Medicare Supplement plan during the initial enrollment period.

After this six-month window, your Medigap options may be limited and policies may cost more.

Keep in mind that some states may have additional Medigap policy open enrollment periods.

Last Modified: May 8, 2023

6 Cited Research Articles

  1. U.S. Centers for Medicare & Medicaid Services. (2022, September). Medicare & You 2023. Retrieved from https://www.medicare.gov/publications/10050-Medicare-and-You.pdf
  2. AARP. (2020, March 25). Do I have to enroll in Medicare at age 65 if I am already collecting Social Security? Retrieved from https://www.aarp.org/retirement/social-security/questions-answers/medicare-enroll-collecting-ss/
  3. Medicare.gov. (2019, September). Understanding Medicare Advantage & Prescription Drug Plan Enrollment Periods. Retrieved from https://www.medicare.gov/Pubs/pdf/11219-Understanding-Medicare-Part-C-D.pdf
  4. Medicare.gov. (n.d.). When can I buy Medigap? Retrieved from https://www.medicare.gov/supplements-other-insurance/when-can-i-buy-medigap
  5. Medicare.gov. (n.d.). When will my coverage start? Retrieved from https://www.medicare.gov/basics/get-started-with-medicare/sign-up/when-does-medicare-coverage-start
  6. Social Security Administration. (n.d.). Medicare Benefits. Retrieved from https://www.ssa.gov/benefits/medicare/