You retire at 65. Your employer offers you COBRA coverage to continue your group health insurance for up to 18 months. It feels like a safe landing: you keep the same doctors, the same coverage, the same pharmacy, and you buy yourself time to figure out Medicare.
For people who are not yet 65, COBRA is often a reasonable bridge. For people turning 65, it is a trap. Here is why.
Medicare has an Initial Enrollment Period centered on your 65th birthday. It lasts 7 months — 3 months before your birthday month, your birthday month, and 3 months after. If you miss this window without a qualifying reason to delay, you face the Part B late enrollment penalty: a permanent 10% increase in your Part B premium for every 12 months you were late.
COBRA does not count as a qualifying reason to delay. Under Medicare rules, "current employer coverage" means insurance through a current job — actively working. The moment you leave your job, you are no longer on current employer coverage, even if COBRA looks and feels exactly like the same plan.
When you leave a job that provided you with qualifying employer coverage, your Special Enrollment Period (SEP) begins — not when your COBRA runs out. The SEP lasts 8 months. If you take COBRA and assume you have 8 months from when the COBRA expires, you may have badly miscalculated. You have 8 months from when you left the job, period.
If you retire in September and your IEP has already closed, take COBRA in October through the following April, and assume your SEP starts when COBRA ends — you may find yourself trying to enroll 9, 10, or 12 months after leaving your job. That is outside the 8-month window. The penalty applies.
There are situations where taking COBRA alongside Medicare enrollment is reasonable. If your employer plan covers your spouse (who is not yet Medicare-eligible), continuing COBRA for your spouse while you enroll in Medicare makes sense. If you left your job during your Initial Enrollment Period and want a month or two on COBRA while your Medicare coverage kicks in, that is manageable. The issue is taking COBRA as a substitute for Medicare enrollment, not as a temporary bridge.
| COBRA + delayed Medicare | Medicare + Supplement or Advantage | |
|---|---|---|
| Typical monthly cost | $600–$1,800 (full premium you previously shared with employer) | $202.90 (Part B) + supplement cost |
| Late enrollment penalty | Permanent if SEP missed | None if enrolled on time |
| Coverage gap risk | High if COBRA ends before Medicare starts | None with proper planning |
If you are currently on COBRA and approaching or past 65, call 1-800-MEDICARE or visit SSA.gov immediately to understand where you stand in your enrollment window. The cost of waiting can be permanent.
Reminder: Ready at 65 is not affiliated with Medicare, CMS, the SSA, or any government agency. This article is general educational information, not financial, legal, medical, or insurance advice. Rules, costs, and deadlines change — verify current details at Medicare.gov or by calling 1-800-MEDICARE before making any decision. Full disclaimer →