Losing job-based coverage after 65: your Special Enrollment Period

If you kept working past 65 and delayed Part B because you had health coverage from your (or your spouse's) current job, you get a Special Enrollment Period when that job or coverage ends. The deadlines are different for each part of Medicare, so it's worth marking them on a calendar.

Part B: up to 8 months

You can sign up for Part B any time while you still have the job-based coverage, or within 8 months after the job or the coverage ends, whichever comes first. Sign up in that window and there's no late penalty. Social Security will ask your employer to confirm your coverage (form CMS-L564).

Medicare Advantage and Part D: only 2 months

To join a Medicare Advantage plan or a Part D drug plan without waiting for Open Enrollment, you generally have 2 full months after the month your employer coverage ends. Drug coverage matters most: going 63 days or more without creditable drug coverage can add a Part D late penalty for life.

COBRA and retiree coverage don't count

The Part B Special Enrollment Period is based on coverage from current employment. COBRA, retiree plans and severance coverage don't qualify. If you switch to COBRA when you retire, your 8 months still start when the job ends, not when COBRA ends. Waiting for COBRA to run out is a common, costly mistake.

Small employers

If your employer has fewer than 20 employees, Medicare usually pays first even while you're working, so you may need Part B as soon as you're eligible. Ask the benefits office how their plan works with Medicare.

Medigap timing

Your 6-month Medigap Open Enrollment Period starts when you're 65 or older and your Part B begins, so delaying Part B while working also delays that window.