Retirement is a major milestone, but the transition from employer-sponsored health insurance to Medicare can feel like navigating a bureaucratic maze. If you are already over 65 and have Medicare Part A (Hospital Insurance) but delayed Part B (Medical Insurance) because you were still working, you are in a common and manageable situation.
Because you have had “creditable” coverage through your employer, you won’t be penalized for signing up now. Here is exactly how to secure your Part B coverage in time for your retirement.
1. Understand the Special Enrollment Period (SEP)
Most people sign up for Part B at age 65. However, if you or your spouse are still working and have health coverage through that job, you can delay Part B without penalty.
When that employment ends, you trigger a Special Enrollment Period (SEP). This period lasts for 8 months, beginning the month after your employment or group health coverage ends (whichever happens first).
Important Note: Do not wait for your COBRA coverage to end before signing up for Part B. COBRA and retiree coverage do not count as “current employment” coverage, and waiting could result in a lifetime late enrollment penalty.
2. The Paperwork You Need
To enroll in Part B after age 65, you generally cannot just click a button online if you are already enrolled in Part A. You must provide proof that you had employer coverage since you turned 65. You will need two specific forms:
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Form CMS-40B (Application for Enrollment in Medicare – Part B): This is your personal application where you state when you want your coverage to begin.
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Form CMS-L564 (Request for Employment Information): This form must be completed by your employer’s HR department. It proves you had group health insurance based on current employment.
3. When to Apply
Since you are retiring in 3 to 6 months, the “sweet spot” to apply is about one month before your current coverage ends. This ensures a seamless transition with no gap in coverage.
For example, if you retire on June 30, you should submit your paperwork in May or early June, requesting a Part B start date of July 1.
4. Step-by-Step Instructions
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Download the Forms: Get the CMS-40B and CMS-L564 from the links provided below.
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Contact HR: Send the CMS-L564 to your employer’s benefits administrator. They need to fill out Section B.
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Complete Your Section: Fill out the CMS-40B. In the “Remarks” section, it is helpful to write: “I am signing up for a Special Enrollment Period. I want my Part B coverage to begin on [MM/DD/YYYY].”
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Submit to Social Security: You can submit these forms in three ways:
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Online: Use the Social Security Special Enrollment Period online portal. You will need to upload digital copies of both forms.
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Fax/Mail: Send them to your local Social Security office.
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In-Person: Visit your local office (it is often best to make an appointment first).
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5. What Will It Cost?
In 2026, the standard monthly premium for Medicare Part B is $202.90. If your modified adjusted gross income from two years ago was above a certain threshold (e.g., $109,000 for individuals), you may pay an IRMAA (Income Related Monthly Adjustment Amount), which is an additional surcharge.
Helpful Resources
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Form CMS-40B: Application for Part B – The primary application form.
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Form CMS-L564: Employment Information – The form your employer must sign.
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SSA.gov: Sign Up for Part B Only – The official Social Security portal for those who already have Part A.
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Medicare.gov: Working Past 65 – A guide on how Medicare coordinates with employer insurance.
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SHIP (State Health Insurance Assistance Program) – Provides free, local, unbiased counseling if you have complex questions.