Medicare ICEP vs. IEP: Understanding Medicare's Enrollment Periods

• by Zia Sherrell, MPH
• January 12, 2024

Trying to understand and remember the various Medicare enrollment periods can be bewildering. It’s essential to know what you can and cannot do during each of the Medicare enrollment periods because different rules may apply to joining, switching or leaving plans during each period.

Your Medicare Initial Coverage Election Period (ICEP) provides your first opportunity to enroll in a Medicare Advantage (Part C) plan. This guide looks at what you can do during the ICEP and how it differs from other Medicare enrollment periods.

What are IEP and ICEP?

The IEP and ICEP are both one-time Medicare enrollment periods. For many beneficiaries, these periods happen at the same time.

• The Medicare Initial Enrollment Period (IEP) is your first opportunity to enroll in Original Medicare, which consists of Part A and Part B and is administered by the federal government. 
  
  
• In contrast, the ICEP is the initial window for people newly eligible for Medicare to enroll in a Medicare Advantage (Part C) plan. 

Private insurance companies sell Medicare Advantage plans that replace your Original Medicare coverage. These options provide at least the same healthcare coverage as Original Medicare. Many people prefer them because they often offer additional benefits, such as prescription drug coverage and wellness benefits. 

How long is the ICEP Enrollment Period?

Your IEP lasts for seven months, beginning three months before your 65th birthday. If you enroll in Medicare parts A and B during the IEP, then your ICEP runs simultaneously. 

Some people choose not to enroll in Medicare Part B during their IEP. This could be because they have health coverage from their own or their spouses’ group health plan through their employer. 

If you enroll in Part B at a later date rather than during the IEP, your ICEP begins three months before your Part B coverage is due to start. It runs until the last day of the month before your Part B coverage begins.

To help explain the difference between the ICEP and IEP, let’s look at some scenarios.

Enrolling in both Part A and Part B during IEP

Let’s say you turn 65 on August 16 and are newly eligible for Medicare. Your IEP begins three months before your birthday month, on May 1. It continues for your birthday month and three months after, ending on November 30.

If you enroll in both Original Medicare Part A and Part B during this period, your ICEP also runs from May 1 to November 30, and you can enroll in a Medicare Advantage plan. 

The Medicare Advantage plan's effective date cannot come before you have Original Medicare Parts A and B.

Enrolling in Part A during IEP but delaying Part B

As before, let’s imagine you turn 65 on August 16 and are newly eligible for Medicare. However, because you’re still employed and have employer group health plan coverage, you decide to enroll in Part A during the IEP and delay joining Part B.

You retire from work the following year, meaning you qualify for a Special Enrollment Period (SEP). During this time, you enroll in Part B, effective April 1.

Your ICEP to join a Medicare Advantage plan runs from January 1 through March 31. Somewhat confusingly, this means the ICEP finishes before Part B coverage kicks-in. 

If you miss the ICEP, then you’ll have to wait until the Annual Enrollment Period (AEP) to join a Medicare Advantage plan. The AEP (sometimes also called the fall Medicare Open Enrollment Period) runs from October 15 through December 7, with coverage beginning January 1 the following year.

If you wish to enroll in a Medicare Advantage plan, it’s essential to understand how the IECP works in your circumstances so as not to miss the enrollment window. To help you, the government provides a Medicare eligibility calculation tool on Medicare.gov, the official website of Medicare.

ICEP and Medicare Part D

You may also enroll in a Medicare Part D prescription drug plan during your ICEP. 

These plans provide coverage for prescription medications as either a standalone plan that can be used with Original Medicare, or as part of a Medicare Advantage plan in what is called a Medicare Advantage Prescription Drug Plan (MA-PD). 

How Do I qualify for an ICEP?

To trigger an ICEP and join a Medicare Advantage plan, you must have both Medicare Part A and Medicare Part B coverage. Also, your permanent residence must be within the service area of your chosen Medicare Advantage plan.  

If you don’t enroll in Part B during the IEP, you cannot enroll in a Medicare Advantage plan at that time. When you enroll in Part B, you can then join a Medicare Advantage plan during the three-month ICEP window.

What is the Medicare OEP?

The term “Medicare Open Enrollment” can be confusing, as there are several enrollment periods that may sometimes be described by this term, even though each period is very different and works differently.

• The Medicare Advantage Open Enrollment Period (MAOEP) runs from January 1 through March 31. It allows people currently enrolled in a Medicare Advantage plan to make a one-time change. For example, you could switch to a different Medicare Advantage plan or disenroll from your Medicare Advantage plan and return to Original Medicare. You cannot change from one Part D plan to another.
  
  
• There is also the fall Medicare Open Enrollment Period (OEP) mentioned earlier, which runs from October 15 through December 7 each year. During the OEP,  you can join, switch or leave a plan, with changes to coverage beginning on January 1 of the following year.

When else can I enroll in a Medicare Advantage plan?

Medicare may sometimes grant a Special Election Period (SEP) if you experience a life-changing event that impacts your health coverage. The length of the SEP depends on the triggering circumstances, which could include things like moving out of your Medicare Advantage plan’s service area, no longer qualifying for Medicaid or leaving a skilled nursing facility.

Learn more about Medicare Advantage plans in your area, explore when you can enroll – even if you're not in your ICEP – and find a plan that fits your coverage needs and your budget.

Or call 1-800-557-6059 1-800-557-6059 TTY Users: 711 to speak with a licensed insurance agent. We accept calls 24/7!

About the author

Zia Sherrell is a digital health journalist with over a decade of healthcare experience, a bachelor’s degree in science from the University of Leeds and a master’s degree in public health from the University of Manchester. Her work has appeared in Netdoctor, Medical News Today, Healthline, Business Insider, Cosmopolitan, Yahoo, Harper's Bazaar, Men's Health and more.

When she’s not typing madly, Zia enjoys traveling and chasing after her dogs.

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