Key Takeaways

• Delaying Medicare Part B while still working may seem logical, but in 2025, there are key reasons why enrolling at age 65 could still benefit you—even with employer coverage.

• The penalties and gaps that come with postponing Medicare Part B can have lasting effects on your healthcare access and financial stability.

Still Working at 65? You Still Have a Medicare Decision to Make

Reaching age 65 is a major Medicare milestone, but not everyone retires at this age. In fact, many people continue working well into their late 60s or even 70s. If you’re one of them, you might assume that enrolling in Medicare Part B isn’t necessary while you have employer-sponsored insurance. But that decision isn’t as straightforward as it may seem.

Medicare Part B covers outpatient services—doctor visits, lab tests, preventive screenings, and more. In 2025, the standard monthly premium for Part B is $185, with an annual deductible of $257. If you’re weighing whether or not to enroll while still working, the choice depends on several factors, including the size of your employer, how your group plan works with Medicare, and potential late enrollment penalties.

Medicare’s Coordination with Employer Coverage

How Employer Size Affects Medicare Rules

Medicare treats employer coverage differently depending on the number of employees:

• 20 or more employees: Your group health plan is the primary payer, and Medicare is secondary. You can delay Part B without penalty if the coverage is creditable.

• Fewer than 20 employees: Medicare becomes the primary payer, and your employer plan is secondary. In this case, failing to enroll in Part B can lead to coverage gaps and denied claims.

In 2025, these rules remain consistent with past Medicare policy. Many people mistakenly assume they can always delay enrollment if they have job-based insurance, but smaller employers can’t legally require their group health plans to pay before Medicare. If you don’t sign up for Part B in these cases, you may be responsible for most medical costs out of pocket.

The Part B Late Enrollment Penalty Still Exists

One of the most important reasons to enroll in Medicare Part B at 65—even while working—is to avoid the late enrollment penalty. If you miss your initial enrollment period and don’t have qualifying coverage, you’ll pay a 10% penalty for each full 12-month period you were eligible but didn’t enroll. This penalty is permanent and adds to your premium for as long as you have Part B.

In 2025, this remains unchanged. If your employer plan is not considered creditable, or you fail to enroll within the required time after it ends, you could be locked into higher monthly costs permanently.

Initial Enrollment and Special Enrollment: Know the Timelines

Your first chance to enroll in Medicare is your Initial Enrollment Period (IEP)—a 7-month window that includes:

• Three months before the month you turn 65

• The month of your 65th birthday

• Three months after your birthday month

If you’re still working and covered by a group plan, you may qualify for a Special Enrollment Period (SEP) when that coverage ends. This SEP gives you 8 months to enroll in Medicare Part B without penalty.

But beware: if you delay enrollment and don’t qualify for an SEP, you’ll have to wait until the General Enrollment Period (GEP)—January 1 to March 31—with coverage starting in July. That gap can leave you without coverage for months.

Weighing Medicare Part B Against Your Employer Plan

What Part B Covers That Many Employer Plans May Not

Even if you’re covered through work, enrolling in Medicare Part B could fill in coverage gaps. Part B covers:

• Outpatient visits

• Preventive screenings (often with no coinsurance)

• Durable medical equipment

• Home health care services

Employer plans can vary significantly in what they offer. High deductibles, coinsurance, and limited networks may leave you with higher out-of-pocket costs compared to Medicare.

By enrolling in Part B while working, you may:

• Avoid late penalties

• Gain secondary coverage that picks up where your employer plan leaves off

• Protect yourself if your employment situation changes unexpectedly

Medicare as Secondary Insurance Can Still Pay Benefits

If your employer plan remains your primary coverage, Medicare Part B still works as a secondary payer. This means:

• Medicare may cover expenses not fully paid by your employer plan

• You may reduce your overall out-of-pocket costs

• You maintain continuity of coverage if you retire suddenly

In 2025, more employers offer high-deductible plans. Medicare Part B can help reduce your exposure to large bills by acting as a back-up payer.

COBRA and Retiree Coverage Are Not the Same as Employer Coverage

A common pitfall is assuming COBRA or retiree health benefits delay your need for Medicare. They do not count as active employment-based coverage.

If you delay Medicare enrollment because you have COBRA or a retiree plan, you will:

• Miss your SEP eligibility

• Be subject to the Part B late penalty

• Possibly face delayed coverage when you do enroll

It’s important to distinguish active employment-based insurance from other types of post-employment health coverage. Only the former can allow a delay in Part B without penalty.

Higher-Income Earners and the IRMAA Factor

In 2025, if your income is above certain thresholds—$106,000 for individuals or $212,000 for couples—you may pay more for Part B due to the Income-Related Monthly Adjustment Amount (IRMAA). This is a sliding scale based on your modified adjusted gross income from two years prior (2023).

Before deciding whether to enroll, consider:

• Whether your IRMAA-adjusted premium is still cost-effective

• How your current employer plan compares in total costs

• Whether combining both plans gives you stronger protection

Even with a higher premium, the added coverage Medicare Part B provides could outweigh the costs, especially for those with complex health needs or higher utilization.

What If You Plan to Work Beyond 70?

There is no penalty for continuing to work past 70, but delaying Medicare beyond this age without creditable coverage leads to the same late penalties and enrollment issues.

If you anticipate working well into your 70s, be sure to:

• Confirm your employer plan is creditable

• Document your coverage

• Mark your calendar for SEP eligibility if you retire

Medicare doesn’t automatically enroll you in Part B if you delay. You must actively sign up within your SEP to avoid penalties and gaps.

How to Enroll in Medicare Part B While Working

If you decide to enroll in Part B while still working, the process in 2025 is straightforward:

• Visit ssa.gov or call Social Security to enroll

• Provide proof of creditable employer coverage if applying during SEP

• Monitor the start of coverage, which may begin the following month depending on your enrollment timing

Enrollment is not automatic unless you’re already receiving Social Security benefits. Take proactive steps to ensure your coverage is set up on time.

Making an Informed Decision Protects You Now and Later

Enrolling in Medicare Part B while still working at age 65 isn’t required—but it may still be the right choice. Your decision should be based on a clear understanding of how Medicare coordinates with your employer plan, the risks of late penalties, and the protection Medicare provides if your work status changes.

If your employer has fewer than 20 employees or your job situation is uncertain, enrolling in Part B can prevent serious coverage gaps. Even in cases where Medicare is secondary, it may reduce your expenses and safeguard your future health needs.

Understand the Real-World Impact of Delaying Medicare Part B

As you plan your Medicare timeline while working, consider every angle—from costs and coverage to penalties and long-term protection. What seems like a smart decision in the short term can become a costly oversight later.

Before making any final choice, it’s best to speak with a licensed agent listed on this website. They can walk you through your options and help you align Medicare enrollment with your current and future health goals.