Missing your Medicare enrollment period can feel stressful, but the good news is that it’s not the end of the road. Whether you forgot to sign up when you were first eligible or simply didn’t realize you needed to take action, there are ways to get Medicare coverage and limit potential penalties.
Each year, Medicare offers specific enrollment windows that allow people to join or change their coverage. If you missed your Initial Enrollment Period, the General Enrollment Period (which runs from January 1 through March 31) may be your next opportunity to sign up.
In this article, we’ll walk through what happens if you miss your Medicare enrollment, how to get coverage now, and what to expect when it comes to costs and late penalties.
Understanding Your Medicare Enrollment Windows
Before looking at what happens if you miss an enrollment, it’s important to understand how these periods work.
Most people first become eligible for Medicare at age 65, and that’s when the Initial Enrollment Period (IEP) begins. This window lasts for seven months: it starts three months before your 65th birthday, includes your birthday month, and ends three months afterward. During this time, you can sign up for Medicare Part A (hospital insurance) and Part B (medical insurance) without penalty.
If you’re already receiving Social Security benefits when you turn 65, you’re automatically enrolled in Part A and Part B. But if not, you need to enroll yourself, either online through the Social Security website or by contacting your local Social Security office.
Some people choose to delay Medicare because they’re still working and have employer coverage through their job or their spouse’s job. That’s perfectly acceptable, as long as the coverage qualifies as “creditable.” When that coverage ends, you’ll get a Special Enrollment Period to sign up without facing a late penalty.
However, if you don’t have other creditable coverage and you miss your Initial Enrollment Period, you’ll need to wait for the next General Enrollment Period to sign up.
The General Enrollment Period
The General Enrollment Period (GEP) runs from January 1 through March 31 each year. This is the window for anyone who missed their initial opportunity to enroll in Medicare Part A and/or Part B.
Before 2023, coverage for people who signed up during this time didn’t begin until July. But thanks to recent updates from the Centers for Medicare & Medicaid Services (CMS), coverage now starts the first day of the month after you enroll.
For example, if you sign up in February, your coverage will begin March 1. This change helps minimize the gap between enrollment and coverage start dates, ensuring beneficiaries can access care sooner.
Once your Part A and Part B coverage begin, you can also enroll in additional coverage like a Medicare Advantage (Part C) plan or a Part D prescription drug plan during a corresponding enrollment window.
Late Enrollment Penalties
Unfortunately, missing your Initial Enrollment Period can sometimes result in financial penalties that stick with you for as long as you have Medicare. Here’s how those work.
Part A Penalty
Most people qualify for premium-free Part A because they or their spouse paid Medicare taxes for at least 40 quarters (10 years). If you don’t qualify for free Part A and you didn’t buy it when you were first eligible, your monthly premium could increase by 10%, and you’ll pay that higher rate for twice the number of years you delayed enrollment.
For instance, if you waited two years to sign up, you’d pay the 10% penalty for four years.
Part B Penalty
The Part B late enrollment penalty is more common. For every 12-month period you could have had Part B but didn’t sign up, your monthly premium increases by 10% and this penalty lasts for the entire time you have Part B.
As an example, if your Part B premium is $202.90 (in 2026) and you delayed enrollment by two full years, you’d pay an additional 20%, bringing your total monthly cost to $243.48. Over time, that can add up.
Part D Penalty
There’s also a penalty for delaying Part D prescription drug coverage if you go 63 or more days without creditable drug coverage after your Initial Enrollment Period. The Part D penalty adds 1% of the national base premium for every month you delayed enrollment. This penalty also lasts as long as you have Part D coverage.
These penalties are designed to encourage continuous coverage and help keep Medicare affordable for everyone. Still, they can be avoided with proper planning, or minimized by acting quickly once you realize you’ve missed a deadline.
Special Enrollment Periods: When You May Not Face a Penalty
If you delayed enrolling in Medicare because you had other qualifying coverage, you might be eligible for a Special Enrollment Period (SEP), which allows you to sign up later without penalty.
The most common situation involves having employer-sponsored health insurance through your job or your spouse’s job. As long as that coverage is considered creditable (meaning it’s as good as Medicare’s), you can delay Medicare enrollment without a penalty.
Your Special Enrollment Period begins when your employment or employer coverage ends (whichever comes first) and lasts for eight months. During this time, you can enroll in both Part A and Part B. If you miss that window as well, you’ll need to wait until the next General Enrollment Period and could face penalties.
Special Enrollment Periods may also apply in other circumstances, such as losing coverage from a union plan, moving out of your plan’s service area, or qualifying for certain assistance programs like Medicaid or Extra Help.
How to Enroll in Medicare After Missing the Initial Period
If you missed your Initial Enrollment Period and now need to sign up, you can apply for Medicare online through the Social Security Administration’s website or by calling or visiting your local Social Security office.
When you enroll during the General Enrollment Period, your Part A and/or Part B coverage will begin the first day of the following month. Once that coverage is in place, you’ll have a chance to add on other types of coverage:
- Medicare Advantage (Part C): You can join a Medicare Advantage plan between April 1 and June 30 after signing up for Part A and Part B.
- Prescription Drug Coverage (Part D): You can also use this same window to add a Part D plan if you didn’t have creditable drug coverage before.
If you’d rather stick with Original Medicare, you can also consider enrolling in a Medicare Supplement (Medigap) plan. Medigap plans help pay for out-of-pocket costs like deductibles and coinsurance. However, if you enroll outside your six-month Medigap Open Enrollment Period, you may be required to answer health questions, and coverage isn’t guaranteed in all cases.
What to Do Next
If you realize you’ve missed your Medicare enrollment, the best thing to do is act quickly. Waiting too long can lead to coverage gaps, late penalties, and higher out-of-pocket costs. Here’s how to get back on track:
- Determine your situation. Did you miss your Initial Enrollment Period entirely, or did you delay Medicare because of other coverage?
- Check your eligibility for a Special Enrollment Period. If you had creditable coverage, you may still be able to sign up penalty-free.
- If you’re not eligible for an SEP, enroll during the General Enrollment Period. The sooner you sign up, the sooner your coverage will begin.
- Explore your additional coverage options. Once you’re enrolled in Parts A and B, consider adding a Medicare Advantage, Part D, or Medigap plan for more comprehensive protection.
Navigating these rules can be confusing, especially when penalties and timing are involved. That’s where working with a trusted Medicare agency can make a real difference.
Let Carolina Senior Benefits Help
At Carolina Senior Benefits, we understand how overwhelming Medicare enrollment can feel, especially if you’ve missed a deadline. Our licensed agents can help you determine whether you qualify for a Special Enrollment Period, explain your options for coverage, and guide you through the enrollment process step-by-step.
We can also help you compare Medicare Advantage, Part D, and Medigap plans so you can find the coverage that best fits your needs and budget. Whether you’re enrolling for the first time or trying to correct a missed deadline, you don’t have to handle it alone.
