When Can I Enroll in Medicare?

For most people, the first opportunity to enroll in Medicare begins around age 65. However, the right time to enroll can depend on whether you are already receiving Social Security benefits, whether you or your spouse are still working, and what type of health coverage you currently have.

For most people who become eligible for Medicare at age 65, the Initial Enrollment Period lasts seven months: the three months before the month you turn 65, the month you turn 65, and the three months after.

Some people can delay certain parts of Medicare without a late-enrollment penalty if they have qualifying group health coverage based on current employment. Other enrollment periods may apply if you miss your first opportunity or experience certain life events.

Understanding which enrollment period applies to you can help you avoid gaps in coverage and potential late-enrollment penalties.

Key Takeaways

Your Medicare Initial Enrollment Period generally lasts seven months.
It begins three months before the month you turn 65 and ends three months after your birthday month.
If you or your spouse are still working and you have qualifying employer group health coverage, you may be able to delay Medicare Part B.
After qualifying current-employment coverage ends, you may have an eight-month Special Enrollment Period to enroll in Part B.
COBRA and retiree coverage are not treated the same as coverage based on current employment for the Part B Special Enrollment Period.
If you miss your Initial Enrollment Period and do not qualify for a Special Enrollment Period, the General Enrollment Period runs from January 1 through March 31 each year.
Medicare Advantage and Medicare Part D have their own enrollment periods and rules.

Your Medicare Initial Enrollment Period

For most people who become eligible for Medicare at age 65, the Initial Enrollment Period is your first opportunity to enroll.

It lasts seven months:

Three months before the month you turn 65
The month you turn 65
Three months after the month you turn 65

For example, if your birthday is in July, your Initial Enrollment Period would generally run from April through October.

If your birthday falls on the first day of a month, your Medicare timing may begin one month earlier.

When your Medicare coverage begins depends partly on when you enroll. If you sign up for Part B before the month you turn 65, coverage generally begins the month you turn 65. If you enroll during your birthday month or during one of the following three months, Part B generally begins the month after you enroll.

Are You Automatically Enrolled in Medicare?

Not everyone has to actively sign up for Medicare.

Some people who are already receiving Social Security or Railroad Retirement Board benefits before becoming eligible for Medicare may be enrolled automatically in Medicare Part A and Part B.

If you are not receiving those benefits, you may need to enroll yourself.

Do not assume that Medicare enrollment will happen automatically. Several months before your 65th birthday, confirm whether you will be automatically enrolled or whether you need to take action.

What If You Are Still Working at 65?

Turning 65 does not always mean you need to enroll in every part of Medicare immediately.

If you or your spouse are still actively working and you have group health coverage based on that current employment, you may be able to delay Medicare Part B without a late-enrollment penalty.

However, not every type of health insurance qualifies.

Before delaying Part B, ask your employer or benefits administrator:

Is my health coverage based on current employment?
Does the employer plan require me to enroll in Medicare at 65?
Which coverage will pay first?
How many employees does the employer have?
What happens to my coverage when employment ends?
Is my prescription drug coverage considered creditable?

Employer size can also affect how your employer plan coordinates with Medicare, so it is important to verify your specific situation before delaying enrollment.

Related topic: Do I Need Medicare If I’m Still Working?

The Part B Special Enrollment Period

If you delayed Part B because you had qualifying group health coverage based on your own or your spouse’s current employment, you can generally enroll in Part B while that coverage continues or during an eight-month Special Enrollment Period after the employment or qualifying job-based coverage ends, whichever happens first.

The eight-month period begins when the employment or qualifying employer coverage ends.

Choosing COBRA afterward does not extend this eight-month period.

If you want Medicare coverage to begin when your employer coverage ends, consider beginning the enrollment process before your employer coverage terminates so you can reduce the risk of a coverage gap.

Does COBRA Let You Delay Medicare?

COBRA is not treated the same as group health coverage based on current employment for the Part B Special Enrollment Period.

If your employment or qualifying employer coverage ends, your eight-month Part B Special Enrollment Period generally begins even if you elect COBRA.

Do not assume that you can wait until COBRA ends before enrolling in Medicare Part B.

If you are approaching Medicare eligibility or leaving a job after age 65, confirm your Medicare enrollment timing before relying on COBRA coverage.

What About Retiree Coverage?

Retiree health insurance can work differently from insurance based on current employment.

A retiree plan may expect Medicare to pay first once you become eligible. In some cases, the retiree plan may not pay properly if you do not have Medicare Part A and Part B.

If you have retiree coverage, contact the plan administrator and ask exactly how the coverage coordinates with Medicare.

The Medicare General Enrollment Period

If you did not enroll in Medicare Part B when you were first eligible and you do not qualify for a Special Enrollment Period, you may be able to enroll during the General Enrollment Period.

The General Enrollment Period runs:

January 1 through March 31 each year.

If you enroll during the General Enrollment Period, your coverage generally begins the first day of the month after you sign up.

Depending on your circumstances, you may also owe a Part B late-enrollment penalty.

When Can You Enroll in Medicare Part D?

Medicare Part D helps cover prescription drugs.

When you first become eligible for Medicare, you generally have an Initial Enrollment Period during which you can enroll in prescription drug coverage.

You can get Part D coverage through:

A stand-alone Medicare drug plan if you have Original Medicare, or
A Medicare Advantage plan that includes prescription drug coverage.

You can also join, switch, or drop Medicare drug coverage during Medicare Open Enrollment, which runs from October 15 through December 7 each year.

If you go 63 consecutive days or longer after your Initial Enrollment Period without Medicare drug coverage or other creditable prescription drug coverage, you may have to pay a Part D late-enrollment penalty if you enroll later.

Related topic: Medicare Part D

When Can You Enroll in Medicare Advantage?

Medicare Advantage is another way to receive your Medicare Part A and Part B benefits through a private insurance company approved by Medicare.

You generally need both Medicare Part A and Part B to join a Medicare Advantage plan.

When you first become eligible for Medicare, you may be able to enroll in Medicare Advantage during your initial enrollment period.

Each year, Medicare Open Enrollment runs from October 15 through December 7. During this period, people with Medicare can make certain changes to Medicare Advantage and prescription drug coverage for the following year.

There is also a Medicare Advantage Open Enrollment Period from January 1 through March 31 for people who are already enrolled in a Medicare Advantage plan. Different rules apply during this period.

What Happens If You Enroll Late?

Missing a Medicare enrollment deadline can have consequences.

Depending on the part of Medicare and your circumstances, you could experience:

A gap in health coverage
A delay before you can enroll
A Part B late-enrollment penalty
A Part D late-enrollment penalty
A premium-Part A late-enrollment penalty if you do not qualify for premium-free Part A

Late-enrollment penalties can sometimes continue for as long as you have the coverage.

Before delaying any part of Medicare, confirm that your existing coverage allows you to delay enrollment without a penalty.

Frequently Asked Questions

Do I have to enroll in Medicare at 65?

Not necessarily.

If you or your spouse are still actively working and you have qualifying group health coverage based on that current employment, you may be able to delay Medicare Part B.

The correct decision depends on your employer coverage, employer size, HSA situation, and how the employer plan coordinates with Medicare.

How long is the Medicare Initial Enrollment Period?

For most people becoming eligible at age 65, the Initial Enrollment Period lasts seven months.

It begins three months before the month you turn 65, includes your birthday month, and continues for three months afterward.

Can I enroll in Medicare after age 65?

Yes.

The enrollment period available to you depends on why you delayed Medicare and what coverage you had.

People with qualifying employer coverage based on current employment may qualify for a Special Enrollment Period. Others may need to use the General Enrollment Period.

How long do I have to enroll in Part B after I stop working?

If you delayed Part B because you had qualifying group health coverage based on current employment, you generally have an eight-month Special Enrollment Period after the employment or qualifying job-based coverage ends, whichever happens first.

Does COBRA extend my Medicare enrollment period?

No.

COBRA does not extend the eight-month Part B Special Enrollment Period associated with qualifying current-employment coverage.

When is Medicare Open Enrollment?

Medicare Open Enrollment runs from October 15 through December 7 each year.

This period is primarily for making changes to Medicare Advantage and Medicare prescription drug coverage. It is not the same as your Initial Enrollment Period for Medicare Part A and Part B.

The Bottom Line

For most people, Medicare enrollment begins with a seven-month Initial Enrollment Period around age 65.

If you continue working and have qualifying employer coverage, you may be able to delay certain parts of Medicare. If that coverage ends, a Special Enrollment Period may allow you to enroll later without a Part B late-enrollment penalty.

The most important step is to confirm which enrollment period applies to your individual situation before a deadline passes.

If you are still working, have employer insurance, COBRA, retiree coverage, or an HSA, review those rules carefully before deciding when to enroll.

Need Personalized Medicare Help?

Medicare enrollment rules can vary depending on your employment, existing health insurance, prescription coverage, and other circumstances.

If you would like help understanding your options, you can request a no-obligation conversation with one licensed Medicare professional.

Get Medicare Help →

Sources

Medicare.gov — When Can I Sign Up for Medicare?

Medicare.gov — When Does Medicare Coverage Start?

Medicare.gov — Working Past 65

Medicare.gov — Joining a Medicare Health or Drug Plan

Medicare.gov — Open Enrollment

Medicare.gov — Special Enrollment Periods