For many Americans, turning 65 used to mean retiring and enrolling in Medicare. But today, that milestone looks different. With rising living costs, longer life spans, and a growing desire to stay active or financially flexible, more people are continuing to work past traditional retirement age.
If you’re working past 65 and wondering what to do about Medicare, you’re not alone. The good news? You have options. But the wrong move—or missed deadline—can cost you in late enrollment penalties or gaps in coverage.
Here’s how to navigate Medicare when you’re still employed at 65 or beyond, and how to make smart decisions based on your job, your health, and your future plans.
Do You Have to Enroll in Medicare at 65?
The short answer is: it depends.
If you’re already receiving Social Security benefits when you turn 65, you’ll be automatically enrolled in Medicare Parts A and B. But if you’re not collecting Social Security and you’re still working, enrollment isn’t automatic—and you get to decide when to enroll based on your current health coverage.
The key question is whether your employer coverage counts as creditable coverage under Medicare rules. If it does, you can typically delay Medicare Part B (and sometimes Part D) without penalties.
Medicare Part A: Most People Should Enroll
Medicare Part A covers hospital care, skilled nursing facility stays, and some home health services. If you or your spouse worked and paid Medicare taxes for at least 10 years, Part A is premium-free.
Even if you’re still working, most people enroll in Part A at 65 because it’s free and may help cover hospital costs not fully paid by your employer plan. The only reason to delay Part A is if you’re contributing to a Health Savings Account (HSA)—more on that below.
Medicare Part B: You May Want to Delay (or Not)
Part B covers doctor visits, outpatient care, and preventive services. It comes with a monthly premium ($174.70 in 2025 for most people) and is optional at age 65 if you have employer-based insurance.
Here’s how to decide:
If your employer has 20 or more employees: You can delay Part B without penalty. Your group health plan is considered primary, and Medicare is secondary.
If your employer has fewer than 20 employees: Medicare becomes your primary insurance at 65, and you should enroll in Part B even if you have group coverage. If you don’t, your job-based plan may not pay for services Medicare would cover, and you could face late enrollment penalties later.
It’s essential to confirm your employer coverage status with HR. Don’t assume—ask directly whether your plan is primary or secondary after age 65.
Medicare Part D: Prescription Drug Coverage and Timing
Medicare Part D helps cover prescription medications. Like Part B, it has a monthly premium and can be delayed if your employer plan includes creditable drug coverage.
Creditable coverage means your plan’s drug benefits are expected to pay, on average, at least as much as standard Medicare Part D coverage. Your employer is required to notify you each year about whether your coverage is creditable.
If it’s not, or if you go 63 days or more without creditable coverage, you’ll face a lifetime late enrollment penalty if you sign up for Part D later.
What About HSAs? A Special Case
If you’re still working and contributing to a Health Savings Account (HSA), enrolling in any part of Medicare—even Part A—disqualifies you from making further HSA contributions.
If you plan to keep funding your HSA, you should delay enrolling in both Part A and Part B. But you’ll need to stop HSA contributions at least 6 months before you apply for Medicare to avoid tax penalties, since Medicare Part A is retroactive for up to 6 months.
This is one area where early planning is critical. Talk to a tax advisor or benefits professional before making decisions about HSAs and Medicare.
When and How to Enroll in Medicare Later
If you delay Medicare because of active job-based coverage, you qualify for a Special Enrollment Period (SEP) when that coverage ends—whether you retire or lose coverage for another reason.
During this SEP, you have 8 months to enroll in Medicare Part B without facing a late penalty. But the SEP for Part D (prescription drugs) is shorter—only 63 days—so be sure to act quickly on both.
You can apply for Medicare during this SEP by contacting the Social Security Administration online or by phone. You’ll likely need proof of coverage from your employer, so don’t delay gathering the paperwork.
What If You Miss Your Special Enrollment Window?
Missing your SEP can be costly. If you don’t sign up for Part B when your job-based coverage ends, you may have to wait until the General Enrollment Period (Jan 1–Mar 31) to apply, and your coverage won’t start until July 1.
Worse, you could face a permanent late enrollment penalty—10% for each 12-month period you were eligible but didn’t enroll. This penalty applies for as long as you have Medicare, so avoiding it is a high priority.
Coordinating Employer Coverage with Medicare
Once you’re enrolled in both Medicare and employer insurance, you need to understand how the two plans interact. Coordination of benefits determines which plan pays first:
If your employer has 20+ employees: Employer plan pays first, Medicare pays second.
If your employer has fewer than 20 employees: Medicare pays first, employer plan pays second.
If you’re self-employed or on COBRA: Medicare typically pays first, and you should enroll in Medicare when first eligible to avoid penalties.
In some cases, having both Medicare and job-based insurance can reduce your out-of-pocket costs. But in others, especially if the employer plan has high premiums or limited networks, Medicare alone may be the better value.
Always compare your total costs—including premiums, deductibles, copays, and drug costs—before deciding to keep both.
What About Retiree or COBRA Coverage?
Employer-sponsored retiree health benefits and COBRA are not considered active employer coverage for Medicare purposes. That means you should enroll in Medicare when you’re first eligible, even if you’re covered by retiree or COBRA insurance.
Failing to do so can lead to denied claims and penalties, since Medicare will be considered your primary coverage after age 65.
If you’re offered COBRA after leaving a job, it can work alongside Medicare for a short time—but it shouldn’t replace Medicare enrollment.
Final Thought
Working past 65 gives you the freedom to choose how and when to enroll in Medicare—but it also comes with responsibility. Understanding how your employer insurance interacts with Medicare can protect you from unnecessary costs, coverage gaps, and enrollment penalties.
Whether you’re planning to work a few more years or keep going indefinitely, make Medicare part of your benefits planning conversation—not an afterthought. Ask questions, review your options, and make decisions that align with both your health and your career goals.
Because turning 65 isn’t just about eligibility. It’s about opportunity—if you know how to take it.
