How to Enroll in Medicare: Step-by-Step Guide for 2026

Written By

Greg Wohl

Licensed Medicare Specialist

Enrolling in Medicare sounds straightforward until you realize there are multiple enrollment windows, different rules depending on whether you are still working, and permanent financial penalties if you miss the wrong deadline. Getting it right the first time matters.

This guide walks you through every Medicare enrollment period, explains exactly how to apply, and covers the special situations - employer coverage, disability, COBRA, and more - that affect when and how you should enroll.

Key Takeaways

Initial Enrollment Period: Most people have a 7-month Initial Enrollment Period (IEP) centered on their 65th birthday
How to Apply: You can enroll online at SSA.gov, by phone, or in person at a Social Security office
Employer Coverage: If you have qualifying employer coverage, you can delay enrollment without penalty
Late Penalty: Missing your enrollment window without a valid exception triggers a permanent Part B late penalty
Parts A and B First: You must be enrolled in Parts A and B before joining a Medicare Advantage or Part D plan
Get Help: A licensed Medicare specialist can help you choose the right plan after you enroll in Original Medicare

Step 1: Understand Your Enrollment Window

Before you apply, you need to know which enrollment period applies to you. There are four main windows:

Enrollment Period	Who It Applies To	When It Occurs
Initial Enrollment Period (IEP)	Everyone turning 65 or newly eligible due to disability	7-month window: 3 months before, birthday month, 3 months after turning 65
Special Enrollment Period (SEP)	People with qualifying employer or union coverage	8 months after employer coverage ends or employment ends (whichever comes first)
General Enrollment Period (GEP)	People who missed their IEP and do not qualify for SEP	January 1 - March 31 each year; coverage starts July 1
Annual Enrollment Period (AEP)	People already on Medicare who want to change plans	October 15 - December 7 each year; changes take effect January 1

The IEP is the most important window. If you enroll in the first 3 months of your IEP, your coverage starts on the first day of your birthday month. If you enroll in your birthday month or the 3 months after, your coverage start date is delayed by 1-3 months.

Step 2: Decide Whether to Enroll Now or Delay

Not everyone needs to enroll at 65. Whether you should enroll immediately or delay depends on your current health coverage situation.

Enroll at 65 if you:

Are not covered by an employer group health plan
Have retiree coverage (retiree plans do not count as qualifying employer coverage)
Are covered by COBRA (COBRA does not count as qualifying employer coverage)
Are covered by a marketplace/ACA plan (marketplace plans do not exempt you from the penalty)
Are covered under a spouse's employer plan where the employer has fewer than 20 employees

You may safely delay if you:

Are actively working and covered by your own employer's group health plan (employer must have 20+ employees)
Are covered by your spouse's employer group health plan (employer must have 20+ employees)

Pro Tip: If you are unsure whether your employer coverage qualifies, ask your HR department for a letter confirming the plan is "primary" to Medicare. This protects you if CMS ever questions your delayed enrollment.

Step 3: Enroll in Medicare Parts A and B

Medicare Parts A and B are administered by the Social Security Administration (SSA), not by private insurers. There are three ways to apply:

Option 1: Apply Online (Fastest)

Go to SSA.gov/medicare and complete the online application. It takes approximately 10 minutes. You will need your Social Security number, date of birth, and information about any current employer coverage.

Option 2: Apply by Phone

Call the Social Security Administration at 1-800-772-1213 (TTY: 1-800-325-0778), Monday through Friday, 8 a.m. to 7 p.m. ET.

Option 3: Apply In Person

Visit your local Social Security office. Find your nearest office at SSA.gov/locator. An appointment is recommended but not required.

Automatic Enrollment

If you are already receiving Social Security retirement or disability benefits, you are automatically enrolled in Medicare Parts A and B when you turn 65 (or after 24 months of disability benefits). You will receive your red, white, and blue Medicare card in the mail about 3 months before your coverage begins.

Note: If you do not want Part B (because you have qualifying employer coverage), you must actively decline it when your card arrives. Instructions for declining Part B are included with the card.

Step 4: Choose How You Want to Receive Your Benefits

Once you are enrolled in Parts A and B, you have a choice about how you receive your Medicare benefits:

Path	What It Includes	Best For
Original Medicare + Medigap + Part D	Parts A and B from CMS, a Medigap supplement plan from a private insurer, and a standalone Part D drug plan	People who want maximum provider flexibility and predictable costs
Medicare Advantage (Part C)	An all-in-one plan from a private insurer that replaces Parts A and B and usually includes Part D	People who want lower premiums, extra benefits (dental, vision, OTC), and are comfortable with a network

You enroll in Medicare Advantage or a standalone Part D plan directly with the private insurer — not through SSA. You can do this during your IEP, or during the Annual Enrollment Period (October 15 - December 7) each year.

A detailed comparison of Medicare Advantage vs. Medigap can help you decide which path is right for your situation.

Step 5: Understand the Late Enrollment Penalties

Missing your enrollment window without a qualifying exception results in permanent financial penalties that are added to your monthly premiums for as long as you have Medicare.

Part	Penalty	How Long It Lasts
Part A	10% higher premium for twice the number of years you delayed (most people get Part A premium-free)	Twice the number of years you delayed
Part B	10% of the standard premium for each full 12-month period you were eligible but did not enroll	Permanent (for life)
Part D	1% of the national base beneficiary premium per month without creditable drug coverage	Permanent (for life)

Example: If you delay Part B enrollment for 2 full years without a qualifying reason, your monthly Part B premium increases by 20% permanently. In 2026, the standard Part B premium is $185/month — a 20% penalty adds $37/month, or $444/year, for the rest of your life.

Use our Medicare penalty calculator to estimate what a late enrollment could cost you.

Special Situations: What to Do If Your Situation Is Not Straightforward

Still Working at 65 With Employer Coverage

You can delay Parts A and B without penalty as long as you are covered by a group health plan through your own or your spouse's current employer (20+ employees). When that coverage ends, you have an 8-month Special Enrollment Period to sign up for Part B without penalty. Do not wait for COBRA to end — the SEP starts when active employment ends, not when COBRA ends.

On COBRA or Retiree Coverage

Neither COBRA nor retiree coverage counts as qualifying employer coverage for Medicare purposes. If you are relying on COBRA or retiree insurance at 65, you should enroll in Medicare during your IEP to avoid late penalties. Medicare will typically be your primary coverage.

Under 65 and Receiving Disability Benefits

If you have been receiving Social Security Disability Insurance (SSDI) for 24 months, you are automatically enrolled in Medicare Parts A and B. Your IEP works the same way as for people turning 65 — you can enroll in a Medicare Advantage or Part D plan during that window.

End-Stage Renal Disease (ESRD)

People with ESRD (permanent kidney failure requiring dialysis or a transplant) qualify for Medicare at any age. Enrollment rules differ — contact Social Security or a Medicare specialist for guidance specific to your situation.

Veterans With VA Coverage

VA benefits do not count as creditable coverage for Medicare purposes. Veterans who rely solely on VA care and skip Medicare Part B may face late penalties if they later want to add Part B. Many veterans choose to enroll in both to maximize their coverage options. See our guide on Medicare issues for veterans for more detail.

What Happens After You Enroll

After your application is processed, here is what to expect:

Medicare card arrives: Your red, white, and blue Medicare card will arrive in the mail within 4-6 weeks of your coverage start date.
Choose a supplement or Advantage plan: You now have a window to enroll in a Medigap plan (with guaranteed issue rights during your first 6 months of Part B) or a Medicare Advantage plan.
Add Part D drug coverage: If you chose Original Medicare, enroll in a standalone Part D plan to avoid the drug coverage penalty. If you chose Medicare Advantage, your plan likely includes Part D already.
Set up premium payments: Part B premiums are typically deducted automatically from your Social Security benefit. If you are not yet receiving Social Security, you will receive a quarterly bill.
Review your coverage annually: Every fall during the Annual Enrollment Period (October 15 - December 7), review your plan to make sure it still meets your needs for the coming year.

Important: Your Medigap open enrollment window — the 6-month period after your Part B effective date when insurers cannot deny you or charge you more due to health conditions — is the single most valuable window in Medicare. Missing it means you may be subject to medical underwriting for the rest of your life. Learn more about Medigap open enrollment.

Frequently Asked Questions

When should I enroll in Medicare?

Most people should enroll during their Initial Enrollment Period, which opens 3 months before the month they turn 65. Enrolling in those first 3 months ensures coverage starts on the first day of your birthday month.

How do I sign up for Medicare?

Apply online at SSA.gov/medicare, by calling 1-800-772-1213, or in person at a Social Security office. If you are already receiving Social Security benefits, enrollment is automatic.

What happens if I miss my Medicare enrollment window?

Without a qualifying exception, you face permanent late enrollment penalties. The Part B penalty is 10% per 12-month period you delayed, added to your premium for life. The Part D penalty is 1% per month without creditable drug coverage.

Do I have to enroll in Medicare at 65 if I still have employer insurance?

No, if you or your spouse is actively working and covered by a group health plan from an employer with 20 or more employees, you can delay without penalty and use a Special Enrollment Period when that coverage ends.

What is the difference between Original Medicare and Medicare Advantage enrollment?

You enroll in Original Medicare (Parts A and B) through SSA. Medicare Advantage and Part D plans are offered by private insurers and enrolled in directly with the plan during your enrollment window. You must have Parts A and B before joining a Medicare Advantage plan.