Each Medicare enrollment period offers different benefits for beneficiaries to enroll. Whether you are new to Medicare or wish to change your Medicare elections, understanding each enrollment period is essential.
Medicare enrollment periods can be confusing because different enrollment periods have different dates for various purposes. There are many enrollment periods for people signing up for Medicare benefits for the first time. When you are new to Medicare, you may not need to apply for benefits. You could be automatically enrolled in Medicare coverage if you meet a few requirements.
If you receive Social Security retirement benefits four months before you turn 65, you will automatically be enrolled in Original Medicare. Thus, you will not need to enroll yourself in Medicare Part A and Part B. If you receive Social Security Disability Insurance (SSDI) you will automatically be enrolled in Original Medicare upon your 25th month of SSDI payments.
If you do not qualify for automatic enrollment, but wish to enroll, you may use your Initial Enrollment Period and begin your Medicare enrollment in Part A, B, or both with Social Security Administration.
Initial Enrollment Period for New Medicare Beneficiaries
Your Initial Enrollment Period (IEP) for Medicare is a seven-month period that allows you to enroll in Medicare Part A and Medicare Part B. This enrollment period begins three months before your 65th birthday or three months before your 24th Social Security disability check, whichever comes first.
During your Initial Enrollment Period, you can enroll in both Part A or Part B of Original Medicare; you can enroll in just Part A and opt to delay Medicare Part B; or you can enroll in just Part B and not Part A because you have a Part A premium you do not wish to or cannot afford. For most, enrolling in Medicare Part A makes sense because for most it has a $0 monthly premium. However, if you have group health coverage due to your or your spouse’s active employment, it is not uncommon to delay Medicare Part B enrollment.
The Initial Enrollment Period begins three months before your Medicare enrollment qualifying event, the month of, and ends three months after your qualifying event. For most, this enrollment period happens around their 65th birth month.
For example, if you turn 65 on June 2, your enrollment period begins on March 1 and ends on September 30. Those with birthdays on the first of the month are considered 65 the month before.
If you enroll in Medicare during the three months before your 65th birthday, your Original Medicare benefits will go into effect on the first day of your birth month. If you enroll during your birth month your Part B coverage will begin on the first day of the following month. If you enroll in the three months following your birth month, coverage will begin on the first day of the following month. Part A benefits, however, will go into effect retroactively up to 6 months but no sooner than ones 65th birth month. This is only true for those who have premium-free Part A. If you have a Part A premium the timing would match your Part B effective date.
Initial Enrollment Period for Individuals on Medicare Before 65
If you receive Medicare benefits before age 65 due to a disability, you will receive another Initial Enrollment when you turn 65.
For example, if you become eligible for Medicare at age 57 due to a disability and refuse Part B at that time, you will be able to enroll for Part B at age 65 with no late enrollment penalties.
This additional Initial Enrollment Period runs the same seven-month period starting three months before the 65th birth month.
During any IEP, there is a parallel initial enrollment period for Medicare Advantage Plans and Medicare Part D plans. Additionally, for those who do not want Medicare Advantage, there is a Medigap Supplement open enrollment period that is tied to the start of Medicare Part B. When your Part B coverage begins, you have a 6-month guaranteed issue period to enroll in any available Medigap (Medicare Supplement) plan. During this time, insurance companies cannot deny you coverage or charge you more based on your health, and medical underwriting is not allowed.
Special Enrollment Period in Medicare
A Special Enrollment Period (SEP) is a limited time when you can sign up for or make changes to your Medicare coverage due to certain life events. Not everyone qualifies, and if you do, you’ll usually need to provide proof of your situation.
Part B (and Premium Part A) – SEP for Employer Coverage
If you delay enrolling in Medicare Part B (or Premium Part A) because you or your spouse are still working and covered by an employer group health plan, you may qualify for a SEP.
Here’s how it works:
- You can enroll in Part B at any time while you or your spouse are actively working and have group coverage.
- Your SEP ends 8 months after either:
- Your employment ends, or
- Your group health coverage ends — whichever comes first.
- If you regain both employment and employer coverage during that 8-month window, your SEP remains open.
Note: Retiree coverage, COBRA, and individual plans do not count as active employer coverage for SEP eligibility.
Part D – SEP for Loss of Creditable Drug Coverage
If you already have Medicare Part A or B and lose creditable prescription drug coverage (like an employer plan), you have a 63-day SEP to enroll in either:
- A Medicare Part D plan, or
- A Medicare Advantage plan with drug coverage (MA-PD)
To avoid a Part D late enrollment penalty, it’s important to enroll as soon as your previous drug coverage ends.
Other Life Events That Trigger a SEP
If you’re already in a Medicare Advantage or Part D plan, you may qualify for a SEP if certain life changes occur, such as:
- You move outside your current plan’s service area
- Your plan stops operating in your area
- You move into or out of a nursing facility
- You gain or lose Medi-Cal (Medicaid) eligibility
- You are approved for or lose Extra Help (Low-Income Subsidy)
Each situation has its own SEP timeline, so be sure to act quickly and check with Medicare or a local HICAP counselor for help.
General Enrollment Period for People Who Miss Enrolling During Both the IEP or SEP
Suppose you miss enrolling in Original Medicare during your Initial Enrollment Period and do not have coverage due to employment that would qualify you for a Special Enrollment Period. In this case, you will need to wait until the General Enrollment Period (GEP) to enroll in Original Medicare.
The GEP runs annually from January 1 to March 31. When you enroll during this time, your coverage will go into effect on the 1st of the next month. Example: You apply in February; your benefits would be effective March 1.
Keep in mind, when you apply for Original Medicare during the General Enrollment Period, you may be responsible for paying a Premium- Part A and/or Part B late enrollment fee. This depends on how long you delayed enrolling when you could have enrolled in SEP. We recommend that you enroll in Medicare using either your IEP or SEP if you have one to avoid paying the late enrollment penalty.
Enrollment Periods for Medicare Supplement (Medigaps) Plans
Your Medicare Supplement Open Enrollment Period begins the 1st day of the month your Medicare Part B becomes effective. This is a six-month enrollment period that grants you a guaranteed issue right for any Medicare Supplement (Medigap) plan you wish to enroll in. However, many carriers allow you to enroll in a Medicare Supplement plan up to two months before your Medicare Part B start date.
A Medicare Supplement plan is essential for Medicare enrollees who wish to pay as little out-of-pocket costs as possible for their healthcare coverage. Medicare Supplement plans cover the costs that Medicare Part A and Part B leave behind, eliminating the high expenses associated with Medicare coverage.
Enrolling in Medigap during a guaranteed-issue period is important. Especially if you have pre-existing conditions that could result in denial of your policy in the future.
If you miss your Medicare Supplement Open Enrollment Period, you can still apply for Medigap coverage throughout the year. However, there is a chance the application can be denied due to health issues that come up in underwriting.
Also, if you sign up for a Medicare Advantage plan during your IEP, you have 12 months to try the Medicare Advantage plan out. If within 12 months you are not happy, you have a guaranteed issue right to a Medigap.
Finally, once you do have a Medigap, it can be switched to another Medigap at any time. To ensure a guaranteed issue, however, use the Birthday rule, which prevents underwriting questions when you switch on your birthday and up to 60 days after. The guarantee only exists when switching to a Medigap Plan with equal or fewer benefits.
Enrollment Periods for Medicare Advantage Plans
An alternative to Original Medicare is Managed Medicare in the form of Medicare Advantage plans.
Medicare Advantage plans are offered through private insurance companies and offer additional benefits to Original Medicare coverage. Often, these plans provide dental, hearing, vision, and drug coverage as well as gym memberships to enrollees. On the other hand, these plans tend to have prior authorization requirements, and unavoidable co-pays and are more restrictive than Original Medicare.
To enroll in a Medicare Advantage plan, you will want to utilize your Medicare Advantage plan’s Initial Enrollment Period. Remember, you must be enrolled in Original Medicare Part A and B to enroll in a Medicare Advantage plan.
If your Part B were delayed, and you use a SEP or GEP to sign up for and have Part B (and Part A already), then you would have three months before Part B starts to enroll in a Medicare Advantage plan.
If you miss your Medicare Advantage plan’s Initial Enrollment Period, you will have to wait until the Annual Enrollment Period to enroll in a Medicare Advantage plan for the following year.
Annual Enrollment Period for Medicare
The Annual Enrollment Period (AEP) for Medicare occurs each year from October 15 to December 7. This AEP allows Original Medicare enrollees to make several changes to their coverage.
These changes include:
- Switching from Original Medicare to Medicare Advantage
- Go from Medicare Advantage to Original Medicare
- Switch from one Medicare Advantage plan to another
- Enroll, change, or drop your Medicare Part D prescription plan
Suppose you use the AEP to return to Original Medicare from Medicare Advantage. In this case, you can then enroll in a Medicare Supplement plan to lower or eliminate your Original Medicare out-of-pocket costs. This plan will begin on January 1 of the following year. However, there is a chance the Medicare Supplement plan application can be denied due to underwriting unless there’s a guaranteed-issue right.
How to Get Help Understanding Medicare Enrollment Periods
It is essential to enroll in Medicare while you have a valid enrollment period. Missing these enrollment periods can lead to late penalties, lack of coverage, or denial of coverage in the future.
To ensure you enroll in the right Medicare plan for you at the right time, we have a team of Health Insurance Counseling & Advocacy Program (HICAP) counselors registered with the California Department of Aging. They are available to help at every step of the Medicare enrollment process. Whether you wish to enroll in a Medicare Part D plan, Medicare Advantage, or a Medicare Supplement plan.
HICAP Counselors do not sell, endorse, and are not affiliated with any insurance companies. Our goal is to inform and educate the community so you can make an informed decision on something as important as your Medicare healthcare insurance.
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