Key Takeaways

• Delaying Medicare Part B can make financial sense in some situations, especially if you’re still working and covered by employer insurance. But delay it incorrectly, and you could face permanent penalties and coverage gaps.

• Understanding how Special Enrollment Periods work and the timelines tied to employer coverage is essential to avoid unexpected costs.

Understanding the Basics of Medicare Part B

Medicare Part B covers outpatient medical services like doctor visits, preventive care, diagnostic testing, durable medical equipment, and outpatient surgeries. In 2025, the standard monthly premium for Part B is $185, and the annual deductible is $257.

Enrollment in Medicare Part B is optional—but only on paper. The truth is, unless you have qualifying coverage from an employer, delaying Part B can trigger late enrollment penalties and months without health coverage.

When You First Become Eligible

Most people become eligible for Medicare when they turn 65. Your Initial Enrollment Period (IEP) spans seven months:

• Three months before your 65th birthday

• The month of your birthday

• Three months after

If you aren’t automatically enrolled and you don’t sign up during this window, you might have to wait until the next General Enrollment Period (GEP), which runs from January 1 to March 31. Your coverage won’t start until July 1, and you could face late penalties.

Why You Might Consider Delaying Part B

In some situations, delaying Part B is not only acceptable—it’s the smart choice. Here’s when it might work in your favor:

Still Working and Covered by Employer Insurance

If you’re actively employed and have health insurance through your job—or your spouse’s job—you may not need Part B yet. The same applies if you’re covered by union-sponsored insurance. The employer must have 20 or more employees for this rule to apply.

In this case, you can delay Part B without penalty and sign up later during a Special Enrollment Period (SEP). The SEP lasts for eight months after your employment or group coverage ends—whichever comes first.

Paying Two Premiums May Not Make Sense

If your employer plan is already serving your needs, paying a second premium for Medicare Part B may not be financially wise. In these scenarios, delaying Part B allows you to avoid unnecessary expenses while maintaining full coverage through your current plan.

But Here’s What Can Go Wrong

Delaying Part B improperly can be more costly than enrolling upfront. These are the most common pitfalls people face.

Late Enrollment Penalty

If you don’t qualify for a SEP and delay Part B, you’ll face a penalty of 10% for every 12-month period you should have had Part B but didn’t. This penalty is added to your premium—and it’s permanent. In 2025, that means paying $203.50 a month instead of $185 if you delayed by just one year.

Coverage Gaps

If you miss your SEP and have to wait until the next General Enrollment Period, you could go without coverage for several months. Medical costs during this time are entirely out-of-pocket—and could derail your financial plans.

The Clock Starts Ticking When Employer Coverage Ends

You have an eight-month Special Enrollment Period to sign up for Part B after you lose employer coverage. But this timeline can be misleading.

What trips up many people is COBRA coverage or retiree health plans. These do not count as active employer coverage for SEP purposes. If you leave your job and continue coverage through COBRA, the clock to enroll in Part B is already running—regardless of how long COBRA lasts.

Waiting until COBRA ends could mean you miss your SEP and face both penalties and delayed coverage.

Coordination of Benefits: How Part B Works With Employer Insurance

If you’re enrolled in both employer insurance and Medicare, it’s important to know who pays first.

• If the employer has 20 or more employees, the employer plan pays first, and Medicare is secondary.

• If the employer has fewer than 20 employees, Medicare pays first, and the employer plan is secondary.

In small companies, failing to enroll in Part B could result in your employer plan denying claims that Medicare would have paid. That means you pay out-of-pocket for services that should have been covered.

Planning Ahead for Retirement

If you’re planning to retire at 66, for example, and have had employer insurance since turning 65, you’ll want to:

• Confirm that your employer coverage was creditable

• Enroll in Part B during the 8-month SEP window after retirement

Do not wait until your employer coverage ends to figure this out. Start preparing a few months in advance to avoid penalties and gaps.

What If You Retired Before Age 65?

If you retired before turning 65 and had no active employer coverage, you should plan to enroll in Medicare Part B as soon as you become eligible. Delaying in this scenario almost always results in penalties, unless you qualify for a Special Enrollment Period due to other qualifying factors.

If You Have TRICARE, VA, or Other Coverage

TRICARE, CHAMPVA, and VA benefits all have their own rules. But if you have any of these and become eligible for Medicare, you’ll likely be required to enroll in Part B to maintain your benefits.

Failing to enroll in Part B may cause your military or VA-related benefits to end or reduce dramatically. Always check with your program administrator before deciding to delay.

How the General Enrollment Period Works in 2025

If you missed both your IEP and SEP, your only option is the General Enrollment Period (GEP), which runs from January 1 to March 31.

In 2025, if you enroll during this window, your Part B coverage begins the first day of the month after you sign up. This is a change from prior years when you had to wait until July 1.

Still, relying on the GEP means you’ll probably face a late enrollment penalty and could experience several months without coverage.

Key Questions to Ask Before You Delay

• Does your current insurance qualify as creditable coverage under Medicare rules?

• Will Medicare be primary or secondary if you keep your current plan?

• Do you understand when your Special Enrollment Period starts—and ends?

• Are you prepared for the costs of a late enrollment penalty?

• Have you reviewed how other benefits (like TRICARE or COBRA) interact with Part B?

The answers to these questions will help you make an informed decision.

Getting the Timing Right Matters Most

Delaying Medicare Part B isn’t always a bad idea, but doing it without understanding the rules can be a costly mistake. The penalties are real, the gaps in coverage are stressful, and the coordination of benefits can get confusing fast.

Before you make a decision, get clear on your timelines and coverage. And if you’re unsure, talk to a licensed insurance agent listed on this website. They can help you determine if delaying is truly in your best interest—or if it’s time to enroll.