Medicare Enrollment 2026: IEP, GEP, SEP & How to Sign Up

Reviewed against Medicare.gov and SSA rules · Last reviewed: June 2026

Signing up for Medicare on time matters: miss your window and you can face lifelong late-enrollment penalties and a gap in coverage. Most people enroll around their 65th birthday during a 7-month Initial Enrollment Period, but there are other windows — GEP, SEP, AEP — for different situations. This 2026 guide explains each enrollment period, when you’re signed up automatically, how to enroll yourself, and how to avoid the penalties.

Your Initial Enrollment Period (IEP)

Your IEP is a 7-month window built around the month you turn 65: the 3 months before your birthday month, your birthday month, and the 3 months after. Enrolling in the 3 months before means coverage starts the first day of your birthday month — the smoothest timing. Sign up later in the window and coverage can be delayed, so enroll early if you want coverage to begin right at 65.

The Medicare enrollment periods at a glance

Are you enrolled automatically?

It depends on whether you’re already receiving benefits. If you’re getting Social Security (or Railroad Retirement) at least 4 months before 65, you’re automatically enrolled in Part A and Part B, and your card arrives in the mail. If you’re not yet collecting Social Security — common for people delaying their benefit — you must sign up yourself through Social Security. Don’t assume it’s automatic.

The General Enrollment Period (GEP)

If you miss your IEP and don’t qualify for a Special Enrollment Period, you can sign up during the General Enrollment Period, January 1 to March 31 each year. Coverage starts the month after you enroll. The catch: you may owe a Part B late-enrollment penalty for as long as you have Medicare, so the GEP is the fallback, not the goal.

Special Enrollment Periods (SEP) for workers

If you (or your spouse) are still working at 65 with employer group coverage, you can usually delay Part B without penalty and sign up later through a Special Enrollment Period — generally while you have the coverage and for 8 months after it ends. This is how millions of workers avoid paying for Part B before they need it. Note: COBRA and retiree coverage do NOT count as active employer coverage for the SEP, so enroll when your active-employment coverage ends.

Late-enrollment penalties

• Part B: your premium rises 10% for each full 12-month period you could have had Part B but didn’t — and you pay it for life.
• Part D: a penalty of roughly 1% of the national base premium for each month you went without creditable drug coverage, added to your premium permanently.
• Part A: most people pay no premium, so no penalty; those who buy Part A can face a penalty too.

These penalties are the main reason to enroll on time or use a valid SEP.

How to sign up

Enroll in Part A and Part B through Social Security — online at SSA.gov, by phone at 1-800-772-1213, or at a local office. For Part D (drugs), Medicare Advantage (Part C), or Medigap, you enroll through Medicare.gov or the private plan once you have Parts A and B. Apply about 3 months before you want coverage to start.

Common mistakes to avoid

• Assuming enrollment is automatic when you’re not yet on Social Security.
• Relying on COBRA or retiree coverage to delay Part B — it doesn’t qualify.
• Waiting until late in your IEP and delaying your coverage start.
• Skipping Part D and triggering a permanent drug penalty.

Related resources

• Medicare Advantage vs Original Medicare 2026 — choose your path before enrolling.
• Medigap plans 2026 — buy during your 6-month guaranteed-issue window.
• Medicare & Social Security: the Part B deduction
• Social Security in 2026: the complete guide

Frequently asked questions

When can I sign up for Medicare?
Most people sign up during their Initial Enrollment Period — the 7 months around their 65th birthday (3 months before, the birthday month, and 3 months after). Other windows include the General Enrollment Period and Special Enrollment Periods.

Am I automatically enrolled in Medicare at 65?
Only if you’re already receiving Social Security or Railroad Retirement benefits at least 4 months before 65. If you’re not yet collecting, you must sign up yourself through Social Security.

Can I delay Medicare if I’m still working?
Yes. If you or your spouse have active employer group coverage, you can usually delay Part B without penalty and enroll later through a Special Enrollment Period — while you have the coverage and for 8 months after it ends.

What is the Medicare late-enrollment penalty?
For Part B, your premium rises 10% for each full 12 months you could have enrolled but didn’t, for as long as you have Medicare. Part D adds about 1% of the national base premium per month without creditable drug coverage.

Does COBRA count for delaying Medicare?
No. COBRA and retiree coverage do not count as active employer coverage for a Special Enrollment Period. Enroll when your active-employment coverage ends to avoid penalties.

What is the General Enrollment Period?
January 1 to March 31 each year, for people who missed their Initial Enrollment Period and don’t qualify for a Special Enrollment Period. Coverage starts the month after you sign up, and penalties may apply.

How do I sign up for Medicare?
Enroll in Parts A and B through Social Security at SSA.gov, by phone, or in person. For Part D, Medicare Advantage, or Medigap, enroll through Medicare.gov or the private plan once you have Parts A and B.

The Guru Gazette is an independent publisher and is not affiliated with Medicare, CMS, or the SSA. This is general information, not insurance advice — confirm your enrollment dates at Medicare.gov and SSA.gov. Last reviewed: June 2026.

Sources

• Medicare.gov — When to sign up for Medicare: https://www.medicare.gov/basics/get-started-with-medicare/sign-up
• SSA — Apply for Medicare: https://www.ssa.gov/medicare/sign-up
• Medicare.gov — Part B late enrollment penalty: https://www.medicare.gov/basics/costs/medicare-costs
• Medicare.gov — Special Enrollment Periods: https://www.medicare.gov/basics/get-started-with-medicare/sign-up/when-does-medicare-coverage-start
• Medicare.gov — Part D late enrollment penalty: https://www.medicare.gov/drug-coverage-part-d/costs-for-medicare-drug-coverage/part-d-late-enrollment-penalty

People Also Ask

How long is the Medicare Initial Enrollment Period?

The Initial Enrollment Period lasts seven months. It includes the three months before the month you turn 65, your birthday month, and the three months after. Signing up in the three months before your birthday month gives the smoothest start, because coverage can begin on the first day of your birthday month.

When does Medicare coverage start if you sign up before turning 65?

If you enroll during the three months before your birthday month, your Medicare coverage generally starts on the first day of your birthday month. Enrolling later in your Initial Enrollment Period delays the start date. That is why signing up early in the window is usually the cleanest way to avoid a gap in coverage.

How does the Part D late-enrollment penalty work?

The Part D penalty applies if you go without creditable drug coverage after you are first eligible. It adds roughly 1% of the national base premium for each month you went uncovered, and the amount is added to your Part D premium permanently. Keeping creditable drug coverage from the start avoids this lifelong surcharge.

How long does the Special Enrollment Period last after employer coverage ends?

For workers delaying Part B through employer group coverage, the Special Enrollment Period generally runs while you still have that coverage and for eight months after it ends. Enrolling within that window lets you avoid the Part B late penalty. Note that COBRA and retiree coverage do not count for this purpose.

Can you enroll in Medicare online?

Yes. Many people enroll online through the official Social Security website, which handles Medicare sign-up. You can also apply by phone or in person at a Social Security office. If you are not automatically enrolled, applying during the right enrollment window helps you start coverage on time and avoid late penalties.

Related guides

• Medicare 2026 Guide
• Medicare vs Medicaid: What’s the Difference? (2026)
• Medicare Parts A, B, C & D Explained (2026)
• Medigap (Medicare Supplement) Plans 2026: Plan G vs N & How to Choose
• Medicaid 2026 Guide
• Social Security 2026 Guide

Reviewed by the Guru Gazette Editorial Review Team · Last reviewed June 2026. Figures are verified against official government sources; see our Fact-Checking Policy.