Medicare offers specific periods during which you can enroll for coverage. The Medicare Open Enrollment Period lasts three months and is the most flexible.

By Noam Flam
Updated June 8, 2020

Medicare Enrollment Periods: The Basics

There are a number of periods in which you can enroll in Medicare. There is an Initial Enrollment Period, a General Enrollment Period, and several others.

Here, we'll be talking about the Open Enrollment Period, a three-month window that allows you to change any and all of your Medicare benefits and plans. There are also a few other periods referred to as Open Enrollment Periods, but they are distinct from this annual three-month period.

When Is Open Enrollment for Medicare?

The Medicare Open Enrollment Period lasts from October 15 to December 7 of each year. The rationale for this time period is that any changes in benefits that you decide on during this period will go into effect on January 1 of the following year, so you have enough time to process all of the changes.

How Does Medicare Open Enrollment Work?

Medicare consists of a few key parts. Original Medicare refers to Part A and Part B, the basic parts of Medicare that cover hospital care and outpatient care. There is also Medicare Part D, prescription drug coverage, and Part C, which allows you to receive Medicare benefits through a private insurance company.

If you would like to make changes to your Medicare coverage, there are options available. If you only have Part A, you can add on Part B, and vice versa.

Part D is offered through private insurance companies, and you may want to keep that coverage but simply switch to a different plan. These are the types of scenarios Medicare Open Enrollment is for: you are able to change any part of your coverage you like, to mix and match the parts.

Want to learn more about your Medicare options?

Annual Open Enrollment and Medicare Advantage

Medicare Advantage plans are a unique offering in the world of Medicare. With Advantage plans, sometimes called Part C plans, you can receive your coverage through a private insurance company rather than through Medicare. This means your coverage will function in the way you are used to from before you received Medicare: your plan may have a specific network, as well as unique benefits, perks and pricing structures.

Many Advantage plans are out there, but one thing holds true for all of them. If you have a Medicare Advantage plan, you can't be enrolled in Part A or Part B. The coverage would overlap, so this protects you from the possibility of accidentally receiving redundant coverage. You can make the switch from Original Medicare to a Part C plan during the Open Enrollment Period.

When Is the Medicare Advantage Open Enrollment Period?

If you have Original Medicare and want to switch over to an Advantage plan, or vice versa, you can make these choices during the Open Enrollment Period. However, in addition to this period, there is also a special Medicare Advantage Open Enrollment Period, lasting from January 1 to March 31. This offers you an additional three months to decide if the Advantage plan you've chosen is right for you.

In addition to this, you are also given an extra three-month Open Enrollment Period if you meet the following conditions:

At any other time of year, these changes may be more difficult to make or may result in additional costs added on.

Medicare Supplement (Medigap) Open Enrollment Period

Medicare Supplement plans, or Medigap, are insurance plans offered by private insurance companies that cover gaps in your Original Medicare coverage. For example, your Original Medicare coverage may have a Part B deductible, and you can find a Medigap plan that pays this for you.

Many Medigap plans are available, but the coverage they offer is standard throughout the country. However, the prices may vary depending on your health conditions and geographic area.

The Medigap Open Enrollment Period is especially important because outside of this period there is no guarantee you will be able to buy a Medigap plan at all. If you try to purchase a Medigap plan outside of the Open Enrollment Period, but don't have any special eligibility conditions, an insurance company may be able to deny you altogether.

When Is the Medicare Supplement Open Enrollment Period

The Medicare Supplement Open Enrollment Period begins as soon as you meet two conditions: you are 65 or older, and you have Medicare Part B. If you fulfill only one of these conditions, then you are outside of the Medicare Supplement Open Enrollment Period.

If you are 65 years old but only have Medicare Part A, then your Medicare Supplement Open Enrollment Period will begin as soon as you get Part B, no matter your age.

This Open Enrollment Period lasts for six months, beginning when these two conditions are met. After these six months are over, getting a Medigap policy can become much harder. It is important to remember you only have this period once, unlike the Annual Open Enrollment Period, which happens every year.

It's also important to remember you can't have a Medigap plan and a Medicare Advantage plan at the same time. If you have Original Medicare, along with a Medigap plan you acquired during the Medigap Open Enrollment Period, and you then switch to a Medicare Advantage plan, there is no guarantee you will be able to get your Medigap plan back if you choose to switch back to Original Medicare.

Special Enrollment Periods

In addition to the above listed enrollment periods, there is also a Special Enrollment Period for Part C and Part D. These periods allow you to get Part C or Part D coverage after you cease being covered by your employer's health insurance plan.

For both parts of Medicare, the period lasts for 63 days after you lose your employer or union healthcare coverage, or when your employment ends, whichever comes first. For Part D, you can also trigger the Special Enrollment Period if these conditions hold for your spouse, as well as if their benefits are from the Veteran's Administration.

Part D Special Enrollment

Part D has a few unique conditions for special enrollment beyond those listed above. Because Part D is offered by private insurance companies, these conditions allow you to enroll in another Part D plan due to conditions that may be out of your control. These conditions are:

  • You move out of the coverage area of your Part D plan

  • You enter or leave a nursing home

  • Your plan's service area changes

  • You receive the Part D Low Income Subsidy

If you meet any of these conditions, you will be able to alter your Part D plan as part of the Part D Special Enrollment Period.

What to Keep in Mind About Medicare Open Enrollment

Enrollment periods are one of the most important things to stay on top of when it comes to changes in your Medicare coverage. Trying to enroll or make changes outside of these periods can be burdensome or downright impossible, so being aware of them as you begin your Medicare coverage or make changes in your coverage is extremely important.

If you want to make changes to your coverage, make sure to check if you are in a Special Enrollment Period, especially if Annual Open Enrollment is a long way away. To learn more about Medicare Open Enrollment, connect with a trusted healthcare professional.

Noam Flam is a professional writer with expertise in healthcare, insurance, and finance.