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IBX Insights

Navigating Medicare Enrollment Periods

By June 6, 2019December 31st, 2020Enrollment Health Insurance Medicare
A woman takes notes while looking at her laptop computer which is sitting on a coffee table.

Original Medicare, the federal program that provides health insurance for Americans age 65 and older, pays for just 80 percent of most covered services. That leaves Medicare beneficiaries responsible for the remaining 20 percent of their bills. Medicare Advantage (MA) and Medicare Supplement plans both help cover those remaining costs, but the two types of plans function differently. Like Original Medicare, both are regulated by the federal government, but unlike Original Medicare, they are administered by private health insurance companies, and there are many plan options available.

If you’re signing up for the first time or you want to change your coverage, you’ll need to comply with established enrollment periods for the plan of your choosing.

Medicare Supplement Enrollment Periods

You must be signed up for both Medicare Parts A and B to enroll in a Medicare Supplement plan (also called a Medigap plan).

  • If you have Original Medicare only, you can sign up for a Medigap plan at any time.
  • The best time to sign up for a Medigap plan is during your Medigap Open Enrollment Period. Your Medigap Open Enrollment Period begins the first month you are 65 or older and enrolled in Medicare Part B and lasts six months. If you keep employer-provided coverage past your 65th birthday, your Open Enrollment Period will not begin until you enroll in Part B. During this time, you can enroll in any Medicare Supplement plan offered in your state, regardless of any pre-existing health conditions, and you won’t pay a higher premium.
  • You can also enroll in a Medigap plan when you have a guaranteed issue right (sometimes also called “Medigap protections”). You receive guaranteed issue rights if you experience a major change that causes you to need to change coverage, such as moving out of your plan’s service area.

Medicare Advantage Enrollment Periods

You must be enrolled in both Medicare Part A and Part B to sign up for a Medicare Advantage plan.

  • Your first opportunity to sign up for an MA plan (sometimes called “Part C”), is during your Initial Enrollment Period (IEP). It lasts seven months: beginning three months before the month of your 65th birthday, your 65th birthday month, and ending three months after the month of your 65th birthday. If you maintain employer-provided coverage and delay signing up for Part B, your IEP begins three months before the month in which you lose your employer-provided coverage and ends three months after the month in which you lose your employer coverage.
  • Each year, you can add or change coverage during the Medicare Annual Enrollment Period (AEP). AEP runs from October 15 through December 7. During this time, you can change from Original Medicare-only coverage to an MA plan; drop your MA plan for Original Medicare; switch between MA plans; or change your prescription drug (Part D) coverage.
  • If you have MA coverage, you can also add or drop that coverage during the MA Open Enrollment Period (OEP). OEP runs from January 1 through March 31. During that time, you can drop your MA coverage and return to Original Medicare or switch between MA plans.

Missing an enrollment period for a Medicare Supplement or Medicare Advantage plan can have costly implications. If you don’t enroll during one of the designated periods, you may be subject to late fees or higher premiums. The good news is there’s plenty of help available to make these enrollment periods easier to navigate.

Visit for more information or contact a licensed insurance agent for advice.

To find out much Medicare could cost based on which parts you sign up for, if you sign up on time or late, and if you choose to get supplemental insurance, watch How much will Medicare cost?

Y0041_HM_19_74920 Accepted 5/16/2019
Website last updated: 4/9/2019


Kortney Cruz

As Senior Vice President of Government Markets at Independence Blue Cross, Kortney provides overall leadership to Independence’s Medicare businesses, including operations, sales and marketing, risk analytics, and performance management, as well as oversight of the company’s Medicare STAR ratings initiatives and marketing Keystone HMO CHIP products and services to the communities we serve, and helping those communities enroll into the Medicare and CHIP coverage they need. She is directly responsible for acquisition and member retention marketing, product development, sales operations, and sales management at Independence in the Medicare and Keystone HMO CHIP area. Her goal is to deliver innovative and value-driven communications, and she is passionate about enriching the connection between Independence Blue Cross and our membership.