Working Past 65? Your Complete Guide to Enrolling in Medicare Part B When You're Ready

By Tyler Dalton, Fee-Free Medicare Advisor. Last updated: November 2025

Turning 65 doesn’t mean you’re ready to retire, and that’s perfectly fine. Thousands of Alabama seniors continue working well past 65, either because they love what they do or because they need the income and health insurance coverage. But staying on your employer’s health plan creates an important question: When and how do I sign up for Medicare Part B?

If you’re still working at 65 with employer coverage, you’re probably not thinking about Medicare yet. But understanding the enrollment rules now can save you from expensive penalties and coverage gaps later. As an Auburn native who’s helped hundreds of East Alabama residents navigate this transition, I’ll walk you through everything you need to know about enrolling in Medicare Part B after 65, including the exact forms you’ll need, the deadlines that matter, and the Alabama-specific resources to help you get it right.

Understanding Medicare Part B: What It Covers and Why It Matters

Before we dive into enrollment timing, let’s clarify what Medicare Part B actually does for you.

Medicare Part B is your outpatient medical insurance. While Part A covers hospital stays and skilled nursing care, Part B handles everything that happens outside those walls: the day-to-day medical care that keeps you healthy. According to Medicare.gov, Part B covers services including doctor visits, preventive screenings, lab work, X-rays, physical therapy, durable medical equipment like wheelchairs or oxygen, and many other outpatient services.

For most Alabamians, Part B coverage is essential once you’re no longer covered by a comprehensive employer health plan. Without it, you’d be responsible for the full cost of doctor visits, diagnostic tests, and preventive care, expenses that can quickly add up to thousands of dollars annually.

The standard Part B premium in 2026 is $202.90 per month, according to the Centers for Medicare & Medicaid Services (CMS). However, higher-income individuals may pay more through Income-Related Monthly Adjustment Amounts (IRMAA). The 2026 Part B deductible is $283. Most people find this cost reasonable compared to the alternative of paying out-of-pocket for medical care or purchasing private insurance at age 65 or older.

The Small Employer Rule: When You MUST Enroll at 65

Here’s a critical rule that catches many working seniors off guard: If your employer has fewer than 20 employees, you must enroll in Medicare Part B when you turn 65, even if you’re still working and have employer coverage.

Why? Because with small employers (under 20 employees), Medicare becomes your primary insurance coverage at 65 by law. Your employer plan becomes secondary, meaning it only pays after Medicare processes claims first. According to Medicare.gov, if you don’t enroll in Part B when you have a small employer plan, your employer plan may refuse to pay claims at all, leaving you responsible for the full cost of your medical care.

This rule exists under federal coordination of benefits regulations. Small employers aren’t required to provide primary coverage to Medicare-eligible employees the way larger employers are. If you work for a company with 15 employees in Auburn or a family business in Opelika with 12 workers, this rule applies to you.

Don’t assume your employer knows this rule or will tell you. Many small business owners aren’t familiar with these Medicare regulations. If you’re approaching 65 and work for a smaller company, contact Dalton Insurance Agency to verify your employer size and understand your requirements. Missing this enrollment can cost you thousands in denied claims.

The 20+ Employee Rule: Your Special Enrollment Period Flexibility

If your employer (or your spouse’s employer) has 20 or more employees, you have much more flexibility. You can delay enrolling in Medicare Part B without penalty as long as you maintain that employer coverage. Medicare recognizes that these larger employers provide creditable coverage that serves as your primary insurance.

This means you can work until 68, 70, or even longer, stay on your employer plan, and enroll in Medicare Part B later when you’re ready to retire, all without facing late enrollment penalties. This flexibility is valuable for Alabama workers who want to maximize their working years and employer benefits.

However, and this is crucial, your Special Enrollment Period (SEP) only lasts for 8 months. According to Medicare.gov, this 8-month window begins the month after your employment ends OR the month after your employer-provided health insurance coverage ends, whichever comes first.

Let’s say you retire from your position at Auburn University in June 2026. Your employer coverage through the university continues through the end of June. Your 8-month SEP starts in July 2026 and runs through February 2027. If you enroll in Part B anytime during those eight months, you’ll avoid penalties.

Miss that window, and you’ll be stuck waiting until the General Enrollment Period (January 1 to March 31 of each year), and you’ll face a late enrollment penalty that increases your Part B premium by 10% for every 12-month period you were eligible but didn’t enroll. For most people, this penalty lasts for life.

COBRA, Retiree Coverage, and Other Plans Don’t Count

This is where many people get tripped up. Your Special Enrollment Period only applies if you have active employer group health coverage from a company with 20+ employees.

Coverage that does NOT qualify for the SEP includes:

• COBRA continuation coverage (even if you’re paying for coverage through your former employer, it’s not active employer coverage)
• Retiree health benefits (these are considered past employment, not current)
• Marketplace plans purchased through Healthcare.gov
• Veterans Affairs (VA) benefits
• TRICARE coverage (unless you’re actively employed by the military as a civilian)
• Individual health insurance policies

If you retire and elect COBRA coverage, your SEP begins the month you retired, not the month your COBRA ends. Many people mistakenly believe they can stay on COBRA for 18 months and then use their SEP, but that’s incorrect. By the time COBRA ends, their 8-month SEP has expired, and they face penalties.

If you’re planning to use any of these coverage types after retirement, enroll in Medicare Part B BEFORE your employment ends to avoid gaps and penalties.

Strategic Timing: When Should Your Part B Coverage Begin?

The Social Security Administration gives you some control over when your Part B coverage actually starts, depending on when you enroll.

If you enroll during your final month of employer coverage or the first full month afterward, you can choose your effective date. Your options are:

• The first day of the month you enroll
• The first day of the following month
• The first day of the second month after enrollment
• The first day of the third month after enrollment

This flexibility lets you align your Part B start date with your employer coverage end date, preventing gaps or unnecessary overlap.

If you enroll during months 2 through 8 of your SEP, your coverage begins automatically on the first day of the month following your enrollment.

For example: You retire from your job at a Troy manufacturing plant on June 15, 2026. Your employer coverage ends June 30, 2026. Your SEP starts July 2026.

• If you submit your Part B application in July 2026, you can choose to have coverage start August 1, September 1, October 1, or November 1.
• If you submit your application in September 2026, your coverage automatically starts October 1, 2026.

Most Alabama seniors find it simplest to enroll during that first month after their coverage ends, giving them maximum control over their effective date.

The Two Essential Forms You Must Submit

Enrolling in Medicare Part B after 65 requires paperwork. Specifically, two forms submitted together to the Social Security Administration.

Form CMS-40B: Application for Enrollment in Medicare Part B

This is your official enrollment application. You can download it from the Medicare.gov website at https://www.cms.gov/Medicare/CMS-Forms/CMS-Forms/Downloads/CMS40B-E.pdf

The form asks for basic information including:

• Your name, Social Security number, and date of birth
• Whether you’re currently enrolled in Part A
• When you want your Part B coverage to begin
• Information about your current or recent employer coverage

Complete every section accurately. If you have questions about how to answer any part of the form, contact Dalton Insurance Agency. We help Alabama seniors complete these forms correctly every week.

Form CMS-L564: Request for Employment Information

This form provides proof that you had creditable employer coverage, which is why you’re eligible for the SEP without penalties. Your employer (or your spouse’s employer, if that’s where coverage came from) must complete this form.

Download it at https://www.cms.gov/Medicare/CMS-Forms/CMS-Forms/Downloads/CMS-L564E.pdf

The form asks your employer to verify:

• The name of the group health plan
• Whether the plan was based on current employment
• The size of the employer (number of employees)
• The dates your coverage was active

Your HR department should be familiar with this form, as they complete them regularly for retiring employees. Give them plenty of notice, as some companies take several weeks to process these requests.

What if your employer can’t or won’t complete the CMS-L564? This happens occasionally, especially with small businesses or if the company has closed. In these cases, Social Security accepts alternative documentation:

• Pay stubs showing health insurance premium deductions
• W-2 forms showing the employer’s name and your employment dates
• Your health insurance card with the group policy number
• A letter from your insurance company confirming your coverage dates
• Tax documents showing health insurance premium payments

The more documentation you can provide, the smoother your enrollment process will be.

How to Submit Your Medicare Part B Application

Once you’ve completed both forms and your employer has filled out the CMS-L564, you have three options for submitting them to the Social Security Administration.

Option 1: Online Through Your My Social Security Account

The fastest method is uploading your documents through your My Social Security account at https://www.ssa.gov/myaccount/

If you don’t already have an account, you’ll need to create one. This requires verifying your identity with personal information, and the process can take 10 to 15 minutes. Once you’re in, you can upload PDF or image files of your completed forms.

Online submission gives you immediate confirmation that Social Security received your documents, and processing typically happens faster than mail submissions.

Option 2: Mail or Fax to Your Local Social Security Office

You can mail or fax your forms to your local Social Security office. In Alabama, you have several options:

Auburn Social Security Office

1210 Bent Creek Road

Auburn, AL 36830

Phone: 1-866-593-0894

Fax: 1-855-864-0423

Opelika Social Security Office

(Auburn office serves Opelika residents)

Alexander City residents can use the Auburn office or contact Social Security at 1-800-772-1213 to find the nearest office.

Troy Social Security Office

Troy residents should call 1-800-772-1213 for the nearest office location, as Troy cases may be handled by the Dothan or Montgomery offices.

Find all Alabama Social Security offices at https://www.ssa.gov/locator

When mailing your forms, send them via certified mail with return receipt requested so you have proof of delivery. Social Security processes mail applications within 2 to 4 weeks typically, though it can take longer during busy periods.

Option 3: In-Person Appointment

You can also submit your forms in person at your local Social Security office, though you’ll need to schedule an appointment first. Call your local office or the national number (1-800-772-1213) to book a time.

In-person submission can be helpful if you have questions about your forms or want immediate confirmation that everything is complete and correct. The Social Security representative can review your application on the spot and let you know if anything is missing.

However, Alabama Social Security offices often have limited appointment availability, especially in smaller cities. You might wait several weeks for an appointment. If you’re approaching the end of your SEP, don’t risk missing the deadline. Submit online or by mail immediately.

What If You’re Already Enrolled in Medicare Part A?

Many Alabama seniors enroll in Medicare Part A (hospital insurance) at age 65 even if they’re still working, because Part A is premium-free for most people who paid Medicare taxes during their working years. It provides valuable backup coverage in case of a serious illness or accident.

If you already have Part A but not Part B, you’ll still follow the same enrollment process described above when you’re ready to add Part B coverage. Submit both the CMS-40B and CMS-L564 forms together.

Your Part A coverage doesn’t automatically trigger Part B enrollment. These are separate decisions and separate enrollment processes. Don’t assume that having Part A means Social Security will automatically add Part B when your employer coverage ends. You must apply.

Common Mistakes That Cost Alabama Seniors Money

After helping hundreds of East Alabama residents navigate Medicare Part B enrollment, I’ve seen the same costly mistakes repeated again and again. Avoid these pitfalls:

Mistake 1: Assuming your employer will notify you when to enroll. Your employer’s HR department isn’t responsible for tracking your Medicare eligibility or enrollment windows. This is your responsibility. Set calendar reminders for your retirement date and your 8-month SEP deadline.

Mistake 2: Confusing COBRA with active employer coverage. Remember, COBRA doesn’t extend your SEP. If you plan to use COBRA after retirement, enroll in Part B before your employment ends.

Mistake 3: Waiting until your coverage ends to start the application process. Gathering forms, getting your employer to complete the CMS-L564, and processing your application takes time. Start the process 2 to 3 months before your coverage ends to ensure seamless transition.

Mistake 4: Not verifying your employer size. If your company recently downsized from 22 employees to 18, the Medicare rules changed. Always verify current employee count, especially at small businesses where numbers fluctuate.

Mistake 5: Forgetting about your spouse’s coverage. If your spouse is still working and you’re on their employer plan, the size of their employer matters, not yours (if you’re retired). Make sure you understand whose coverage is the primary factor.

Mistake 6: Missing the 8-month deadline. Life gets busy after retirement. Don’t let your SEP slip by. The penalty for late enrollment can add $18.50 to $37 or more to your monthly premium for life. That’s $222 to $444+ per year, every year.

What Happens If You Miss Your Special Enrollment Period?

If you miss your 8-month SEP window, you’ll need to wait until the next General Enrollment Period, which runs from January 1 through March 31 each year. Your coverage won’t begin until July 1 of that year.

This creates a coverage gap. If you miss your SEP in February 2026, you’ll wait until January 2027 to enroll, and your coverage won’t start until July 2027. That’s over a year without Part B coverage, a risky proposition at age 66 or older.

Additionally, you’ll face the late enrollment penalty: 10% added to your monthly Part B premium for every full 12-month period you should have been enrolled but weren’t. If you were eligible for Part B for two years before enrolling, your penalty is 20%, which means your premium increases from $202.90 to $222 per month (using 2026 rates). This penalty continues for as long as you have Part B coverage, typically for life.

The penalties are waived only if you can prove you had qualifying employer coverage during that period. This is why keeping documentation of your employer coverage (pay stubs, insurance cards, W-2 forms) is essential, even years later.

Do You Need Medicare Part B If You Have VA Benefits or TRICARE?

Veterans and military families often ask whether they need Medicare Part B if they have VA healthcare or TRICARE coverage.

VA Healthcare: VA benefits and Medicare don’t coordinate with each other. You can have both, but they work independently. According to the VA, VA coverage doesn’t prevent the Part B late enrollment penalty if you miss your enrollment window. Most Alabama veterans with VA access still enroll in Medicare Part B at 65 or when they retire, because:

• Not all healthcare providers accept VA coverage, but nearly all accept Medicare
• Medicare provides coverage when traveling outside the VA system
• Having both gives you more flexibility and provider choices

TRICARE: TRICARE beneficiaries must enroll in Medicare Part A and Part B when eligible at 65 to keep their TRICARE coverage. If you don’t enroll in both parts, you lose TRICARE coverage. TRICARE becomes your secondary coverage, paying after Medicare processes claims first.

If you have VA benefits or TRICARE, contact Dalton Insurance Agency to discuss how Medicare fits into your coverage strategy. These situations are complex, and the rules differ based on your specific benefits and circumstances.

After Part B: What About Medicare Supplements and Prescription Drug Coverage?

Enrolling in Medicare Part B is just one piece of your Medicare puzzle. Once you have Part B coverage active, you’ll want to consider:

Medicare Supplement (Medigap) Insurance: Original Medicare (Parts A and B) leaves you responsible for deductibles, coinsurance, and copayments that can add up to thousands annually. Medicare Supplement plans fill these gaps, covering most or all of your out-of-pocket costs.

In Alabama, if you enroll in a Medicare Supplement plan within 6 months of your Part B effective date, you have guaranteed issue rights. Insurance companies must sell you a policy regardless of your health conditions, and they can’t charge you more for pre-existing conditions.

Miss this 6-month window, and you may face medical underwriting, higher premiums, or even denial of coverage. This is one of your most valuable Medicare rights. Don’t waste it.

Medicare Part D Prescription Drug Coverage: If your employer coverage included prescription drug benefits and that coverage is ending, you’ll want to enroll in a Medicare Part D plan. You have a 63-day window after your employer coverage ends to enroll in Part D without penalty.

Alabama seniors have multiple Part D options through carriers like Humana, Aetna, WellCare, and others. The right plan depends on your specific medications, preferred pharmacies, and budget.

Medicare Advantage as an Alternative: Instead of Original Medicare with a Supplement and Part D plan, you might consider a Medicare Advantage plan, which bundles Parts A, B, and D together with additional benefits. Alabama has numerous Medicare Advantage options through Blue Cross Blue Shield, Humana, UnitedHealthcare, and regional carriers.

These decisions are complex and highly personal. What works for your neighbor in Auburn may not be right for you in Troy or Alexander City. Your medications, doctors, health conditions, budget, and travel habits all factor into the best choice.

This is where working with a local Medicare expert becomes invaluable.

Why Work with Dalton Insurance Agency?

As an Auburn native and fee-free Medicare advisor, I specialize in helping East Alabama seniors navigate Medicare enrollment, from Part B applications to Supplement plan selection to Part D enrollment. We serve Auburn, Opelika, Alexander City, Troy, Dadeville, and surrounding communities.

When you work with us, you get:

• Personalized guidance on your Part B enrollment timing based on your specific employment and coverage situation
• Help completing your CMS-40B and CMS-L564 forms correctly to avoid processing delays
• Coordination with your employer to ensure timely completion of employment verification
• Analysis of your Medicare Supplement and Part D options once your Part B coverage is active
• Ongoing support as your Medicare needs change over the years

Our services cost you nothing. We’re compensated by insurance carriers when you enroll in coverage, but you pay the same premiums whether you work with us or go direct. The difference is you get expert, local guidance through the process.

I’ve helped hundreds of Alabama seniors successfully enroll in Medicare Part B during their Special Enrollment Period without penalties, coverage gaps, or confusion. We know the Alabama Social Security offices, the local Medicare Supplement carriers, and the specific issues that East Alabama seniors face.

Take Action Now: Your Medicare Part B Enrollment Checklist

If you’re working past 65 or planning to retire soon, use this checklist to stay on track:

90 Days Before Retirement:

• Verify your employer size (current employee count)
• Confirm your exact coverage end date with HR
• Create or log into your My Social Security account
• Download forms CMS-40B and CMS-L564
• Contact Dalton Insurance Agency for a Medicare planning consultation

60 Days Before Retirement:

• Complete your CMS-40B form
• Submit CMS-L564 to your employer HR department for completion
• Begin researching Medicare Supplement and Part D options
• Document your current medications and doctors

30 Days Before Coverage Ends:

• Collect completed CMS-L564 from your employer
• Submit both forms to Social Security (online, mail, or in-person)
• Confirm submission receipt
• Schedule Medicare Supplement consultation with Dalton Insurance Agency

Within First Month After Coverage Ends:

• Verify Part B effective date with Social Security
• Enroll in Medicare Supplement plan (within 6-month guaranteed issue window)
• Enroll in Part D prescription drug coverage (within 63 days)
• Update healthcare providers with new Medicare information

Within 8 Months of Coverage Ending:

• Confirm Part B enrollment is complete if you delayed application
• Ensure you’re not approaching the SEP deadline without action

Your Medicare Journey Starts Here

Working past 65 gives you valuable extra years of income, employer benefits, and professional fulfillment. But when you’re ready to retire and transition to Medicare, understanding the Part B enrollment process is essential to avoiding costly penalties and coverage gaps.

The rules around employer size, Special Enrollment Periods, and required documentation can feel overwhelming. You don’t have to figure this out alone.

Contact Tyler Dalton at Dalton Insurance Agency today for your free Medicare Part B enrollment consultation. We’ll review your specific situation, clarify your timeline, help you with the required forms, and ensure a smooth transition from employer coverage to Medicare.

Dalton Insurance Agency

Serving Auburn, Opelika, Alexander City, Troy, Dadeville, and East Alabama

Phone: 855-593-1446

Website: daltoninsurance.biz

Call today. Your future self will thank you for getting this right the first time.