If you are thinking of enrolling in a Medicare Advantage plan, also known as Medicare Part C, or already have such a plan, you need to pay close attention to established enrollment periods. These are specific times of the year when you can enroll in a new plan or change plans. If you miss the enrollment period, you must wait to enroll for several months until the next enrollment period comes around.

Initial Enrollment Period (IEP)

You become eligible for enrolling in Original Medicare when you turn 65. It is important to recognize the basics behind the Initial Enrollment Period:

  • For three months before your birthday, the month of your birthday, and three months after, you can elect to enroll in a Medicare Advantage plan.
  • Anytime during the next 12 months, you can drop the Advantage plan and go back to Original Medicare.
  • If you are under 65 years of age and have been receiving disability for 24 months, at month 25, you can sign up for a Medicare Advantage Plan.
  • If you delay enrolling in Medicare Part B because you have continued to work and have coverage under your employer’s plan, and then retire or otherwise lose your health insurance, you have eight months from the date you lose your coverage to enroll in Original Medicare or a Medicare Advantage plan.

Annual Open Enrollment Period

If you do not enroll in a Medicare Advantage plan during your Initial Enrollment Period, you have another opportunity during the Annual Open Enrollment Period, note the following:

  • The Annual Open Enrollment period occurs between October 15 through December 7.
  • During this time, you can enroll in a new Medicare Advantage plan or change from one Medicare Advantage plan to another one.
  • During this time, you can also drop your Medicare Advantage plan and return to Original Medicare. All changes will take effect on the upcoming January 1.

Medicare Advantage Open Enrollment (Medicare Part C Enrollment Periods)

From January 1 to March 31, if you are already enrolled in a Medicare Advantage plan, you can switch to a different Medicare Advantage plan. You may also drop your Medicare Advantage plan and return to Original Medicare.

If you are enrolled in Original Medicare, you cannot switch to a Medicare Advantage plan during this time.

Special Enrollment Period (SEP)

There are Special Enrollment Periods that accommodate life changes. Some examples include:

  • If you initially enrolled in a Medicare Advantage plan during your IEP, you can drop the advantage plan anytime during the first 12 months and return to Original Medicare. If you do this, for 63 days after you return to Original Medicare to enroll in a Medicare Supplement plan. You have the same right to drop a Medicare Supplement plan if that was what you chose for your initial enrollment, and enroll in a Medicare Advantage plan.
  • You move, and your current plan does not provide coverage in your new area. Your opportunity to switch plans begins one month before your move and ends two full months after your move.
  • You move and although your current plan does provide coverage, there are new options available to you. This also provides you three months, one month before the move and two months after, to change your Medicare Advantage plan.
  • You have been living out of the U.S. and just moved back. You have two full months after your move to join a Medicare Advantage plan.
  • You have moved home after being confined to a nursing home, rehabilitation center, or other institution. You have two months after the move to join an advantage plan.
  • You were released from prison. You have two months from the date of your release to join an advantage plan.
  • You lost other coverage, for example, you are no longer eligible for Medicaid or the employer-provided healthcare coverage you opted for in lieu of Original Medicare is no longer available to you.
  • You believe you were given misleading information and made the wrong choice of plans.

Medicare Enrollment Period Chart

The chart below provides the full scope of Medicare-related enrollment periods which includes Original Medicare and enrollment periods relating to Medicare Part C (Advantage), Medicare Part D (Prescription Drugs), etc.

Medicare Enrollment Period Chart

  • Initial Enrollment Period (IEP):
Beneficiaries can enroll in Original Medicare, Medicare Part D, and a Medicare Advantage plan for a 7-month period. The period covers the 65th birthday month, the previous 3 months, and the following 3 months. The period will start in the previous month for people with a birthday on the first day of the month.
  • Medicare Advantage -Initial Coverage Election Period (ICEP):
This period runs concurrently with the IEP and represents the 7-month period Medicare enrollees can join a Medicare Advantage plan. For individuals who are just qualifying into Medicare they can enroll in an Medicare Advantage plan during ICEP.
  • Initial Enrollment Period 2 (IEP2):
The government provides this enrollment period for people who could enroll in Medicare before turning 65 because of a qualifying illness or disability. It works the same as the IEP.
  • Special Enrollment Periods (SEP):
Some people have special circumstances that allow them to enroll in Medicare Part D or Medicare Advantage outside of the regular enrollment periods. The SEP generally lasts for 60 days after the qualifying event. People who don’t enroll in Part B because they have job-based health insurance also get an SEP after losing this coverage, which lasts eight months.
  • Medicare Part B Special Enrollment:
Medicare-eligible people who delayed Part B enrollment because of creditable coverage from a job may have up to eight months after that coverage ends to enroll in Part B.
  • General Enrollment Period (GEP):
Eligible people who missed their IEP can enroll in Medicare Part A and Part B from January 1 to March 31. These people can also enroll in Part D from April 1 to June 30.
  • Medicare Supplement (aka Medigap) Open Enrollment:
This is a one-time only 6-month enrollment period, typically occurring when a person ages into Medicare at 65 providing new beneficiaries with the Guaranteed Issue Rights to Medigap plans. For individuals receiving Medicare Part B before their 65th birthday their Medigap OEP starts the first day of the month they turn 65 as well. If there is an enrollment delay going past turning 65 then the Medigap OEP will automatically start the month of enrolling in Medicare Part B.
  • Fall Open Enrollment Period (AEP):
This can also be referred to an open enrollment period (OEP). It is purposed for dropping, changing or joining: Medicare Advantage and/or a Part D plan. This time period is between October 15th to December 7th. This period enables enrollees to make a greater number of changes vs the Medicare Advantage Open Enrollment Period (MAOEP). Changes take effect January 1st.
  • Medicare Advantage – Open Enrollment Period (MAOEP):
This limited Open Enrollment Period runs between January 1st to March 31st. Enrollees in MA plans can switch or drop Medicare Advantage to return to Original Medicare and enroll in a stand-alone Part D drug plan. This difference from AEP in the sense that you cannot make the following changes during this period: switch from Original Medicare to an MA plan, join a Medicare Part D (prescription plan) if on Original Medicare, or switch from one Part D plan to another if on Original Medicare.


  1. Understanding Medicare Advantage and Medicare Drug Plan Enrollment Periods, Medicare.
  2. Special Enrollment Periods Sign Up, Medicare.
  3. How do Medicare Advantage Plans Work?, Medicare.