The COBRA-to-Medicare trap
COBRA can keep your health plan going after a job ends. It does not keep you safe from Medicare’s late-enrollment penalty — and the clock most people think COBRA pauses is actually already running.
COBRA lets you keep the exact health plan you had at work after you leave a job, for up to 18 months, if you pay the full premium yourself. For someone leaving work at 63 or 64, that can look like a bridge all the way to Medicare. The mistake it invites is assuming COBRA also bridges the Medicare enrollment clock. It does not.
| How long | Generally 18 months after a qualifying event like job loss, for employers with 20 or more workers. |
|---|---|
| What it costs | The full premium — employee and employer share combined — plus up to a 2% administrative fee. Often several times what was deducted from a paycheck. |
| What you get | Generally the same group coverage active employees have. You cannot switch to a different plan through COBRA, but if the employer changes its plan for active employees — a new carrier, a different network, adjusted benefits — that change applies to your COBRA coverage too. |
| The election window | Generally 60 days from losing coverage or from the COBRA notice, whichever is later, to elect it. |
Where it goes wrong at 65
| The key deadline: 8 months | If you’re 65 or older when you stop working or your employer coverage ends, whichever happens first, you generally have 8 months to sign up for Part B without a penalty. Choosing COBRA does not extend it. |
|---|---|
| COBRA is not creditable coverage for Part B | Medicare does not treat COBRA as coverage based on current employment, and does not count losing COBRA as a qualifying event for a new Special Enrollment Period. It does not delay or excuse Medicare enrollment the way an active employer plan does. |
| The clock starts at job loss, not at COBRA’s end | The 8-month window starts the day active employment (and the group health plan that came with it) actually ended — not when COBRA runs out, even if you elect COBRA immediately. |
| The penalty is permanent | Miss the window while relying on COBRA and the Part B late-enrollment penalty — roughly 10% of the premium for each full 12-month period you could have enrolled but did not — applies for as long as you have Part B, which for most people is the rest of their life. |
| Part D is treated differently | Some COBRA plans do include creditable drug coverage for Part D purposes, but this has to be confirmed with the plan directly — it is not automatic the way it is not automatic for Part B either. |
Also on The Second Half Guide The airport help you’re entitled to, and nobody mentions Wheelchairs, escorts through the terminal, help through security — all free and yours by law. Almost entirely unused, because nobody tells you. Read it →COBRA and an active employer plan can look identical from the inside — same card, same network, same premium structure minus the employer’s share. Medicare does not see them the same way.
What actually protects you
The safe route is enrolling in Medicare on the 8-month clock described above, regardless of what COBRA is doing. That clock is distinct from the seven-month Initial Enrollment Period centered on turning 65, covered in more detail in the Medicare enrollment deadline piece on this site — the seven-month window is for people with no other coverage delaying them; the 8-month window described here is specifically for people who had active employer coverage and are enrolling after it ends. If you are still actively working at or after 65 with employer coverage, that active coverage is what opens the 8-month window once it ends — COBRA taken after that does not reopen or extend it.
- If you are turning 65 while on COBRA, enroll in Medicare on schedule anyway. Do not wait for COBRA to run out.
- Confirm directly with your COBRA plan administrator whether the drug coverage is creditable for Part D — do not assume it, either way.
- How Medicare affects COBRA depends on which coverage came first: Medicare warns that COBRA you already have will probably end once you enroll in Medicare afterward — confirm your plan’s specific rule rather than assuming either way.
- If you are unsure whether your situation counts as “active employment” coverage versus COBRA continuation, that distinction is the one to get an SSA or SHIP counselor to confirm before assuming either way.
- COBRA does not postpone your Medigap Open Enrollment Period. That six-month federal window generally begins when you are 65 or older and enrolled in Part B, whether or not other coverage continues alongside it.
Eighteen months of COBRA feels like a plan. The Medicare clock underneath it runs on its own schedule regardless, and the penalty for guessing wrong about that does not go away once you notice it.
This is general information, not personal advice. We report the rules, the numbers and the deadlines as clearly as we can. We don't know your income, your state, your health or your family — and all four can change the answer. Treat this as a good place to find the right questions, not a substitute for someone looking at your actual situation.
Where these facts come from
Checked on 27 August 2026 against the sources listed below. Dollar limits and program rules change — if you're reading this well after that date, verify the numbers at the links below.
- CMS — COBRA Continuation Coverage — https://www.cms.gov/cciio/programs-and-initiatives/other-insurance-protections/cobra_fact_sheet
- U.S. Department of Labor — FAQs on COBRA Continuation Health Coverage for Workers — https://www.dol.gov/agencies/ebsa/about-ebsa/our-activities/resource-center/faqs/cobra-continuation-health-coverage-workers
- Medicare — Part B late enrollment penalty — https://www.medicare.gov/basics/costs/medicare-costs/avoid-penalties
- Medicare — COBRA coverage — https://www.medicare.gov/basics/get-started-with-medicare/medicare-basics/working-past-65/cobra-coverage
- Medicare — Special Enrollment Periods — https://www.medicare.gov/basics/get-started-with-medicare/get-more-coverage/joining-a-plan/special-enrollment-periods
Edward Silva
Edward spent more than forty years as a computer professional — long enough to pick up one useful occupational habit: when somebody hands you a summary, go and read the actual documentation. He started The Second Half Guide after noticing that most writing aimed at people his age was either talking down to him or quietly selling him something, and that the plain facts — the dates, the thresholds, the dollar figures — were somehow the hardest part to find.
He's married, with two grown sons, both married themselves. He is not a financial adviser, an attorney or an insurance agent, and this site doesn't tell you what to do with your money. It tells you what the rules actually say, and links to where he checked.