Your employer plan is ending. The clock that matters most starts the day it does — here's how to land without a gap, a penalty, or the one mistake that costs the most.
What's actually happening
If you delayed Medicare because you had real, active employer coverage, you've been doing the right thing. But the day that coverage ends, the responsibility quietly shifts to you. Medicare won't sign you up — and the window to do it on your own terms is generous, but it does close.
The two clocks that matter
Window 1 · Enrollment
Starts the month your employment or the coverage ends — whichever comes first. Enroll in Part B inside it to avoid a lifetime late penalty.
Window 2 · Protection
Losing employer coverage can open a roughly 63-day window to buy a Supplement with no health questions asked. Don't sit on it.
Do it in this order
Ask HR or your benefits administrator for the exact last day of your coverage. Every clock on this page counts from that date.
File before the gap opens — you'll typically need a form to enroll CMS-40B and proof of employer coverage CMS-L564 so it counts as on-time. Submit both through Social Security.
Original Medicare with a Supplement, or Medicare Advantage. Decide inside your guaranteed-issue window, while a Supplement can't ask health questions.
Pick up Part D (or a plan that includes it) within 63 days of losing creditable drug coverage, or a separate lifetime penalty can attach.
Wait for your cards and a confirmation that coverage is live. Don't schedule non-urgent care for the seam between the two plans.
The one trap to avoid
It's the most common — and most expensive — mistake here. COBRA and retiree coverage don't count as active employer coverage for Part B. Taking COBRA instead of enrolling can quietly start the penalty clock and leave you with a gap when COBRA ends.
If you're being offered COBRA as you leave a job at or past 65, enroll in Part B on time anyway — and use COBRA only to round out the rest, if at all. Ask Fern whether COBRA fits your situation →
Tell Fern your last day of coverage and whether COBRA is on the table. Fern sorts what matters and tells you what to verify next. Not a sales tool. Not a plan picker.
Talk it through with Fern →Not leaving work yet? You can wait — there's nothing to do until your end date is set. Come back then.
Just turning 65 instead? →Want free, unbiased help from a local counselor? Find your SHIP counselor — federally funded, no plans to sell.
You can ask Fern a question in plain language, find the path that fits your situation, or get the Sunday Letter — one note a week, no pressure.
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