Enrolling in Medicare After Employer Coverage Ends: What to Do and When

Losing employer health coverage—whether from retiring, a layoff, or cutting back hours—often means it’s time to move onto Medicare. The key is acting quickly so you don’t face gaps in coverage or late enrollment penalties.

Step 1: Confirm Whether You Qualify for a Special Enrollment Period

If you delayed Medicare because you had active employer coverage (from your own job or a spouse’s) and that coverage is now ending, you typically qualify for a Medicare Special Enrollment Period (SEP).

You generally get an 8‑month SEP to enroll in:

• Medicare Part B (medical insurance)
• Medicare Part A (if you didn’t take it at 65)

This SEP usually starts the month after your employer coverage or employment ends, whichever comes first. COBRA, retiree coverage, or severance benefits do not count as active employer coverage and do not extend your SEP, even if you can keep them for months or years.

Step 2: Gather the Right Proof of Coverage

To use your SEP for Part B, you usually need:

• Form CMS‑L564 (Request for Employment Information) completed by your employer, verifying your group health coverage, and
• Form CMS‑40B (Application for Enrollment in Part B).

These forms show Medicare you had qualifying coverage and help you avoid late enrollment penalties.

Step 3: Enroll in Part A and Part B

If you’re not already enrolled:

• Submit CMS‑40B and CMS‑L564 to Social Security (online upload, mail, or local office).
• If you already have Part A and only delayed Part B, you still use these same forms to add Part B.

Enrollment timing affects when coverage starts. If you enroll while you still have employer coverage or in the first month after it ends, your start date is typically aligned to minimize gaps.

Step 4: Decide How You’ll Get the Rest of Your Medicare Coverage

Once you have Parts A and B, choose how to get full coverage:

• Stay with Original Medicare (Parts A and B) and consider:

  • A Medigap (Medicare Supplement) policy to help with deductibles and coinsurance.
  • A stand‑alone Part D plan for prescription drugs.

• Or enroll in a Medicare Advantage (Part C) plan, which usually includes drug coverage and may add extra benefits, but uses plan networks and rules.

Losing employer coverage also creates a separate SEP to:

• Join, switch, or drop a Medicare Advantage plan, and
• Join or switch a Part D prescription drug plan.

These SEPs are generally shorter (often 2–3 months), so check your specific dates carefully.

Step 5: Watch for Penalties and Coverage Gaps

You can face lifetime late enrollment penalties if:

• You go too long without enrolling in Part B after losing employer coverage, or
• You go 63 days or more without creditable prescription drug coverage before enrolling in Part D.

To protect yourself:

• Do not rely on COBRA alone to delay Medicare.
• Make sure to have a Part D plan or other creditable drug coverage in place soon after employer coverage ends.

Understanding your Special Enrollment Period, using the correct forms, and choosing a coordinated Medicare option promptly will help you transition off employer coverage smoothly and avoid costly penalties.