Though the Centers for Medicare and Medicaid Services (CMS) manages the Medicare program, most people sign up through the Social Security Administration (SSA). (Former railroad workers are the only people who do not sign up for Medicare through Social Security.)

The easiest, quickest way to enroll in Medicare is online, which you can do here. If you are a retired railroad worker, contact the Railroad Retirement Board (RRB) toll-free at 1-877-772-5772 (TTY 1-312-751-4701) to speak to an RRB representative Monday through Friday from 9 AM to 3:30 PM.

How to sign up for Medicare online

Enrolling in Medicare online is a simple process that typically takes less than 10 minutes. It's also available 24 hours a day, 7 days a week. In other words, you don't have to schedule an appointment or worry about calling during designated business hours when you apply.

Usually, you don't need much more than your birthdate and place of birth to complete the application. If you have Medicaid, other health insurance, or are a permanent resident, however, you may need to provide the following:

• Group plan information
• Employment information (if your group plan is through an employer)
• Medicaid number
• Permanent Resident Card number

You will also need to create a my Social Security account (click here to either log into or create your account) to make sure Social Security has the correct information. If your information does not match what they have on record, you may be unable to complete an online application.

You can also apply for retirement and/or spousal benefits at the same time. This checklist from SSA explains all of the documents and information you should gather ahead of time.

Do I have to sign up for Medicare online?

While online enrollment is the easiest and the fastest way to apply, it is not the only way. You may also call toll-free at 1-800-772-1213 (TTY 1-800-325-0778) Monday through Friday from 7 AM to 7 PM. Remember to consider any holidays that might change these available days if you choose to sign up over the phone.

If you wish to apply in person, locate your local SSA office here. You will need to call ahead to schedule an appointment.

Is Medicare enrollment automatic?

For some people, Medicare enrollment is automatic.

• If you live in the U.S. and started receiving RRB or Social Security benefits at least four months before your 65th birthday, you are automatically enrolled in Medicare Parts A and B (also known as Original Medicare).
• Residents of Puerto Rico are automatically enrolled in Part A, but need to sign up for Medicare Part B.
• Enrollment is also automatic if you collect disability benefits from the RRB or Social Security, with those under the age of 65 qualifying at their 25th month of disability benefits.

If you are diagnosed with amyotrophic lateral sclerosis (ALS, or Lou Gehrig's disease), your Medicare coverage begins automatically the first month you collect disability benefits.

Patients who receive a diagnosis of end-stage renal disease (ESRD) are not automatically enrolled in Medicare, but they are eligible. For full benefits for services such as dialysis or transplants, you need to sign up for both Medicare Part A and Part B.

When can I sign up for Medicare?

The best time to sign up for Medicare is during your Initial Enrollment Period (IEP). If you miss your IEP, you must wait for the Medicare General Enrollment Period (GEP).

When is your Initial Enrollment Period?

The Initial Enrollment Period is different for everyone. It begins three months before the month you turn 65 and lasts through the three months following your birth month. So, if you turn 65 on June 15, your IEP starts on March 1 and ends on September 30. If your birthday falls on the first of the month, though, that window opens and closes one month earlier – February 1 through August 31 if your 65th birthday falls on June 1.

If you sign up for Medicare during the three-month period before your 65th birthday, you can make sure you have coverage the month you turn 65. Signing up after that three-month window delays your coverage start date for one to three months, depending on when you enrolled.

Failing to sign up during your IEP can lead to lifelong late enrollment penalties if you do not have creditable coverage elsewhere. For coverage to be considered creditable, you must be actively employed at a company that has more than 20 employees.

You can also avoid these penalties if you qualify for a Special Enrollment Period (SEP). There are dozens of ways to qualify for an SEP. The full list can be found on Medicare.gov.

When is the General Enrollment Period?

The Medicare General Enrollment Period is every year from January 1 through March 31. Once you sign up for Medicare Part A and/or Part B, you then have from April 1 through June 30 to choose a Medicare Part D prescription drug plan. This is also when you can join a Medicare Advantage plan. (You must maintain prescription drug coverage or face late fees when you do finally join a Part D plan.)

The coverage selections you make during GEP take effect the following month. If your Initial Enrollment Period includes January, February, or March, enrolling during this time would still be considered your IEP.

What is the late enrollment penalty for Medicare Part A?

If you or your spouse worked and paid Medicare taxes for 40 quarters (about 10 years), you qualify for premium-free Part A. For those who did not earn the 40 credits, the Medicare Part A premium is $506 in 2023.

The late penalty is 10 percent of your monthly premium, for twice the number of years you delayed enrollment. For example:

• Delaying enrollment for 12 months = 2 years of penalty payments
• Delaying enrollment for 24 months = 4 years of penalty payments

And so on. This penalty is only accrued any time a full 12 months passes without being enrolled in Medicare Part A.

What is the late enrollment penalty for Medicare Part B?

The Medicare Part B late enrollment penalty is 10 percent for every 12-month period you did not have Part B, but could have. For example:

• Delaying enrollment for 12 months = 10 percent penalty
• Delaying enrollment for 24 months = 20 percent penalty

And so on. In 2023, the standard Medicare Part B premium is $164.90. Your premium may be higher if your household income exceeds $97,000 (filing single) or $194,000 (filing jointly).

The Part B penalty is different from the Part A penalty in that you have to pay the fee the entire time you have Medicare. This is why it is important to complete your sign-up process during your IEP.

What is Medicare Part D?

Prescription drug coverage is not included in Original Medicare. This coverage comes from a Medicare Part D prescription drug plan or a Medicare Advantage plan that includes drug coverage (known as a Medicare Advantage Prescription Drug plan, or MA-PD). If you are automatically enrolled in Medicare, you still need to sign up for Part D. You can sign up for a Part D plan during your IEP or when you first sign up for Medicare upon leaving an employer's health plan. If you are already enrolled in Medicare, you can choose a Part D plan during the Annual Enrollment Period (AEP), which is October 15 to December 7.

If you wish to avoid paying late fees, and you do not have creditable drug coverage elsewhere, you need to have a Medicare Part D plan. You begin accruing late fees any time you go 63 days or more without prescription drug coverage. The penalty is based on the national base beneficiary premium (which changes every year) and the number of months you go without drug coverage.

The national base beneficiary premium in 2023 is $32.74. You pay 1 percent of this amount for every month without coverage, with the total being rounded to the nearest dime. The amount is added to your monthly Part D premium the entire time you have Medicare. So, if you went 10 months without a Part D plan:

$32.74 x 10% = 3.274, rounded to the nearest dime = $3.30

If you have prescription drug coverage elsewhere, your plan should send you a notification that your coverage is creditable (considered equal to Medicare in terms of pricing and coverage) when you first enroll, as well as every year you have the plan. Be sure to save these notices as proof of creditable coverage when you eventually do choose a Part D plan.

When to sign up for Medigap

Once you've signed up for Medicare Parts A and B and ensured you have proper prescription drug coverage, there are other Medicare options to consider. This is a perfect time to add a Medicare Supplement plan, or Medigap, to help cover some of your out-of-pocket costs. Though the plans are offered by private insurers, Medicare requires they be standardized. Which means that, though costs vary by provider, every Medigap Plan A (or B, C, etc.) provides the same benefits as every other Medigap Plan A.

It is recommended that you enroll in a Medicare Supplement plan during your Medigap Open Enrollment Period (OEP), which begins the first month you are both 65 or older AND enrolled in Medicare Part B. Your Medigap OEP is one of the few times you have guaranteed issue rights, so you cannot be denied a plan or charged more for it – even if you have pre-existing medical conditions. Outside of your OEP, the application goes through the medical underwriting process. This involves answering a variety of health-related questions, such as:

• Age
• Family and personal medical history
• History of tobacco use
• Weight

When you don't have guaranteed issue rights, coverage can be denied based on your answers to any of these questions.

Signing Up for a Medicare Advantage plan

Your Initial Enrollment Period is also a great time to look at enrolling in a Medicare Advantage plan, also known as Medicare Part C. To sign up for Part C, you must first be enrolled in Parts A and B. Advantage plans offer the same level of coverage as Original Medicare, with over 90 percent offering additional benefits. Common extras include:

• Hearing aids
• Prescription drug coverage (called an MA-PD plan)
• Routine dental care
• Routine vision care

Since Medicare Advantage plans are sold by private insurance companies, benefits and costs vary by plan and provider.

In addition to your IEP, if you are currently enrolled in Medicare, you can sign up for Part C during the Annual Enrollment Period, from October 15 through December 7. AEP options include:

• Buying a new Part D prescription drug plan
• Leaving a Medicare Advantage plan to return to Original Medicare
• Leaving Original Medicare for a Medicare Advantage plan
• Switching from one MA plan to another

If you already belong to an MA plan, you may also make changes during the Medicare Advantage Open Enrollment Period, from January 1 through March 31. OEP options include:

• Leaving an MA plan to return to Original Medicare
• Switching from one MA plan to another
• Purchasing a standalone Part D plan if your changes result in a loss of prescription drug coverage

During your first year with an Advantage plan, you may also drop it and return to Original Medicare outside of any enrollment period as long as:

• You act within the first 12 months
• It's your first Advantage plan

After that, the only other time you can sign up for or leave Medicare Part C is if you qualify for an SEP.

To view and compare Medicare Advantage plan options, you can use our Find a Plan tool or call us toll-free to speak to one of our knowledgeable, licensed Medicare agents.