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Enrollment Periods - which one applies to you?

There are many different enrollment periods in Medicare, which vary in duration and applicability. Enrolling into the right parts/plans during the corresponding periods is essential to avoiding late enrollment penalties, getting 'guaranteed issue rights', and most of all to not having gaps in your healthcare coverage.

Enrollment Periods - which one applies to you?

The various Enrollment Periods defined by Medicare can be quite confusing. This handy guide will help you in understanding and tracking your status and enrolling at the right time.

Note that the enrollment periods for different Parts are not always the same. Understanding them, therefore, is crucial.

These are the various types of enrollment periods for Medicare:

  • IEP (Initial Enrollment Period),
  • GEP (General Enrollment Period),
  • SEP (Special Enrollment Period),
  • AEP (Annual Election Period),
  • MA OEP (Medicare Advantage Open Enrollment Period), and
  • Medicare Supplement OEP (Medicare Supplement Open Enrollment Period).

Initial Enrollment Period (IEP)

When you turn 65 and become eligible to apply for Medicare based on age, you can do so during the IEP which starts 3 months before the month you turn 65 and runs for 3 months after, for a total duration of 7 months.

During the IEP, you are eligible to enroll in any of the four Parts of Medicare (Part A, Part B, Part C and Part D). However, if you have alternate equivalent coverage e.g. from an existing qualified employer, you may defer your enrollment to a later date. If you defer without having equivalent coverage, late penalties may be assessed when you do signup at a later time.

Keep in mind that there are dependencies. You must be eligible for  Part A and enrolled in Part B in order to join a Part C (Medicare Advantage) plan. To join a standalone Part D plan (Prescription Drug Plan or PDP), you should be eligible for Part A and/or enrolled in Part B or in some cases a Part C (Medicare Advantage) Plan without prescription drug coverage.

Many MA plans bundle PDP coverage and are called MA-PD Plans, which maybe a worthwhile option to consider.

General Enrollment Period (GEP)

You can also signup for Part A or Part B during the GEP which runs from January 1st to March 31st for coverage effective July 1st of that year.

Note that late enrollment penalties may be assessed if applicable.

Special Enrollment Periods (SEPs)

Special Enrollment Periods (SEPs) vary in duration and scope. You may be eligible for one if your situation changes, usually for a valid reason outside your control, and you wish to enroll in or change your plans.

Some common examples of SEPs are (this is not a comprehensive list):

  • You deferred enrollment in Medicare since you had alternate equivalent coverage, which is now going to end,
  • Your plan is moving outside of your service area,
  • You are moving to a new location which is outside the geographical coverage of your existing plan, or
  • Your plan misled you during enrollment or has been cited/sanctioned by CMS.

Note that, as mentioned above, the SEPs vary in duration and also in scope (which Parts of Medicare you can enroll in or change), depending upon the situation.

Annual Election Period (AEP)

Those who have Medicare can enroll in or change their Part C (Medicare Advantage) and/or Part D (Prescription Drug or PDP) plans during the AEP which runs from October 15th to December 7th of each year. Or they can switch back to Medicare Parts A & B. New plans are effective January 1st of next year.

Even if you are happy with your current Medicare plan(s) and do not want to change, it is a good practice to check what is available in the market as newer plans may be available which fit your needs better. Or your existing plans may have changed some of the benefits. It is always good to check and make sure that you continue to have the right plans for your needs.

Medicare Advantage Open Enrollment Period (MA OEP)

Previously you could disenroll from your Medicare Advantage Plan and go back to Medicare Part A and Part B during Jan 1st - Feb 14th of each year. This offered a way out for those who were not satisfied with the MA plan they chose during the previous AEP.

Beginning 2019, the MA Disenrollment Period is being replaced with the Medicare Advantage Open Enrollment Period (MA OEP) which runs Jan 1st - Mar 31st each year. During this time, you may change your Medicare Advantage Plan or go back to Medicare Part A and Part B, though there are exceptions. Note that either the 'from' MA Plan or the 'To' MA Plan or Both can be with or without prescription drug coverage but you will not be able to enroll into a new standalone Part D Plan for prescription drug coverage unless you switch back to Medicare Part A and Part B.

Medicare Supplement Open Enrollment Period (OEP)

If you are interested in getting a Medicare Supplement plan, keep track of your OEP which starts the month you turn 65 and also have Part B, and runs for six months. Sometimes the AEP or MA-OEP are also referred to as OEP so make sure you understand the context and what is being discussed.

During the Medicare Supplement OEP, you can get a Medicare Supplement plan with ‘guaranteed issue rights’ i.e. without any underwriting. This means that Medicare Supplement plans cannot charge you more for health conditions. Outside of the OEP, Medicare Supplement plans can ask you to undergo medical tests, charge you more for health conditions or for overall poor health and can even deny coverage outright.

There are some SEPs during which you may have ‘guaranteed issue rights’ for Medicare Supplement plans. However, based on your situation, you may or may not qualify for those SEPs. The OEP is a great opportunity to enroll into a Medicare Supplement plan, if you wish to do so.


Click here to learn more about Medicare, its various Parts, different enrollment periods and your costs. 

We have also created videos to help you better understand various topics related to Medicare. Select and watch a video explaining the topic of your interest in a simple and intuitive manner.

Remember that you cannot choose just any combination of Parts and Plans. Let Lighted Road Insurance guide you step-by-step through the Medicare ecosystem and help you in selecting the right plan(s) for your needs. 

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Last Updated: 01-10-2021