Navigating your Medicare enrollment can feel complicated, but it all comes down to timing. Medicare has specific timeframes, called enrollment periods, when you can sign up for coverage for Original Medicare or private Medicare plans, or make changes to your existing plan. Understanding which period applies to you is the key to avoiding coverage gaps and potential penalties.
The main enrollment periods you need to know are:
Below, we'll break down what each of these periods means for you.
Your Initial Enrollment Period is the 7-month window when you can first sign up for Medicare. You can sign up for Medicare Part A, Part B, Medicare Supplement, Part D or Medicare Part C (Medicare Advantage). Though you cannot sign up for both Medicare Supplement and Medicare Advantage. For most people, this period begins 3 months before the month you turn 65, includes the month of your 65th birthday, and ends 3 months after the month you turn 65. For example, if your 65th birthday is in June, your IEP runs from March 1 to September 30.
What’s great about your Initial Enrollment Period is that if you enroll in Original Medicare (namely Part B) you can enroll in a Medicare Supplement plan without underwriting, guaranteeing you coverage. Learn more about Medicare Supplement (Medigap) Open Enrollment Period below.
It is critical to enroll in Medicare during your IEP if you are not covered by other creditable health insurance (like a plan from a current employer). If you delay enrollment in Part B or Part D, you may face late enrollment penalties, which are added to your monthly premiums for as long as you have the coverage.
If you have to buy Part A and you don't buy it when you're first eligible for Medicare, your monthly premium may go up 10%. You'll have to pay this penalty for twice the number of years you didn't sign up. For instance, if you waited two years to sign up, you'll have to pay the penalty for four years.
Note: Most people qualify for premium-free Part A, so this would not apply in those cases.
The Part B late enrollment penalty is an extra 10% of the standard monthly premium for each year that someone delays enrolling in Part B after becoming eligible, unless they have a Special Enrollment Period. You will have to pay this penalty for as long as you have Medicare Part B.
The Medicare Part D late enrollment penalty occurs when you do not join a Medicare drug plan when you first get Medicare, and go 63 days or more without creditable drug coverage — coverage that's similar in value to Part D.
The General Enrollment Period is for individuals who did not sign up for Medicare Part A and/or Part B during their Initial Enrollment Period and do not qualify for a Special Enrollment Period.
Important: Late enrollment penalties may apply if you enroll in Medicare for the first time during the GEP.
This is the best time to buy a Medicare Supplement (Medigap) policy. It's a 6-month period that starts on the first day of the month in which you are both 65 or older and enrolled in Medicare Part B. During this time, insurance carriers cannot use medical underwriting to decide whether to sell you a policy or how much to charge you.
The Medicare Open Enrollment Period (also officially known as the Annual Enrollment Period or Annual Election Period) is your chance each year to review your current coverage and make changes. Your health needs and plan options can change, so it's a good idea to re-evaluate your plan every year.
Any changes you make will take effect on January 1 of the following year.
Life changes can happen at any time, and Medicare has provisions for that. A Special Enrollment Period allows you to make changes to your Medicare coverage outside of the standard enrollment periods due to specific life events. You generally have a limited time to act after the event occurs.
Common qualifying life events for an SEP include:
Life changes can happen at any time, and Medicare has provisions for that. A Special Enrollment Period allows you to make changes to your Medicare coverage outside of the standard enrollment periods due to specific life events. You generally have a limited time to act after the event occurs.
Common qualifying life events for an SEP include:
When you're ready to sign up for Medicare through the Social Security Administration, it's helpful to have some information handy. Be prepared to provide:
Taking a few simple steps before your enrollment period begins can make the process much smoother.
Understand Your Options: Learn the fundamental differences between Original Medicare (Parts A & B), Medicare Advantage (Part C), and Medicare Supplement (Medigap) plans.
Your Initial Enrollment Period (IEP) is a 7-month window that starts 3 months before the month you turn 65, includes your birthday month, and ends 3 months after. If you're already receiving Social Security, you may be enrolled automatically. If you have employer coverage, different rules apply — a licensed advisor can help you determine the right timing.
Missing your IEP can result in lifelong late enrollment penalties. The Part B penalty is 10% of the premium for every full 12-month period you were eligible but didn't enroll. This penalty is added to your monthly premium permanently. For Part D, the penalty is 1% of the national base premium for each month you went without creditable coverage.
Most people pay $0 for Part A (hospital coverage) if they or their spouse paid Medicare taxes for 40+ quarters. Part B (medical coverage) costs $202.90/month in 2026 at the standard rate, though high earners pay more through IRMAA surcharges. You'll also pay a $283 annual deductible for Part B before coverage kicks in.
If your employer has 20+ employees and you have active group coverage, you can delay enrolling in Part B without penalty. You'll qualify for a Special Enrollment Period (SEP) when your employer coverage ends. However, if your employer has fewer than 20 employees, Medicare becomes your primary insurer at 65 and you should enroll on time.
Medicare is federal health insurance primarily for people 65+ (or with certain disabilities), regardless of income. Medicaid is a joint federal-state program for people with limited income and resources, available at any age. Some people qualify for both — known as "dual eligibles" — and may receive additional benefits and cost-sharing assistance.
Have more questions? Browse our complete FAQ library or call 1 (855) 665-9200
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