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I didn’t enroll in Medicare Part B when I turned 65 because I was still working: Can I enroll now?

Deciding to delay Medicare Part B because you are still working is a common financial strategy. Since Part B requires a monthly premium ($202.90 for most in 2026), many choose to stick with their employer-sponsored insurance to avoid paying for dual coverage.

 

The short answer is yes, you can enroll now, and if you meet certain criteria, you can do so without facing the dreaded late enrollment penalty. However, the “how” and “when” depend entirely on your current employment status and the size of your company.

 

1. The Key: The Special Enrollment Period (SEP)

If you delayed Part B because you (or your spouse) were still actively working and had “creditable” group health coverage, you qualify for a Special Enrollment Period (SEP). This is a protected window that allows you to sign up for Medicare without waiting for the general enrollment dates and without paying a 10% penalty for every year you delayed.

 

When does the SEP happen?

You can sign up for Part B at any time while you are still covered by the group health plan. Once that employment or the health coverage ends (whichever happens first), a 8-month window begins.

 

Crucial Note: Do not wait for the full 8 months to pass. While the law gives you 8 months to sign up for Part B, you only have 2 months to sign up for Part D (prescription drug coverage) or a Medicare Advantage plan without a penalty.

 

2. Qualifying for the Penalty-Free Enrollment

To avoid the permanent late enrollment penalty, your situation must meet these three conditions:

  • Active Employment: The insurance must be based on current employment.

     

  • Company Size: Generally, the employer must have 20 or more employees. If you work for a small business (under 20 employees), Medicare is usually required to be your primary insurer at age 65. If you missed this, you might already be accruing penalties.

     

  • Creditable Coverage: Your employer plan must be considered “creditable,” meaning it pays out at least as much as a standard Medicare plan.

     

What about COBRA or Retiree Insurance?

A common misconception is that COBRA or retiree health plans count as “active” coverage. They do not. If you are on COBRA or a retiree plan, your 8-month SEP began the month you stopped working, not when the COBRA coverage ends. If you wait until COBRA runs out to apply for Part B, you will likely face a lifetime penalty and a gap in coverage.

 

3. How to Enroll Now

If you are currently in your SEP, you cannot simply use the standard online “Initial Enrollment” portal in the same way a 65-year-old would. You need to provide proof that you had employer coverage since you turned 65.

Step 1: Complete the Forms

You will need two specific forms:

  1. CMS-40B: The Application for Enrollment in Medicare Part B.

  2. CMS-L564: The Request for Employment Information. Your employer (or former employer) must fill out Section B of this form to verify your coverage dates.

     

Step 2: Submit to Social Security

You can submit these forms online via the Social Security website, or mail/fax them to your local Social Security office.

 

4. What if I Don’t Qualify for a Special Enrollment Period?

If you stopped working more than 8 months ago, or if your employer had fewer than 20 employees and you didn’t realize you needed Medicare, you must use the General Enrollment Period (GEP).

  • When: January 1 – March 31 each year.

     

  • Coverage Start: The first day of the month after you sign up.

  • The Penalty: You will likely pay a 10% surcharge on your Part B premium for every 12-month period you were eligible but not enrolled. This penalty stays with you for as long as you have Medicare.

     

5. Helpful Resources

Navigating Medicare rules can be dense. Use these official resources to ensure you are following the 2026 guidelines: