CALIFORNIA MEDICARE GUIDE
COBRA and Medicare in California: Why Your Part B Deadline Still Matters
A plain-language guide to how COBRA works with Medicare and why COBRA usually does not extend the Part B enrollment deadline.
COBRA can continue job coverage, but it changes the Medicare question
COBRA may let you keep an employer group health plan for a limited time after employment or dependent coverage ends. That continuation can be valuable, but Medicare does not treat COBRA as coverage based on current employment for the Part B Special Enrollment Period.
If you are eligible for Medicare and have COBRA without being enrolled in Medicare, Medicare says the COBRA plan may pay only a small part of your health care costs. Ask the COBRA administrator—in writing—how the plan coordinates with Medicare and what it expects you to enroll in.
The Part B clock is tied to work and active coverage
For the common current-employment Special Enrollment Period, the eight-month window ends eight months after the employment or active group health coverage ends, whichever happens first. Choosing COBRA does not restart or extend that window. Waiting until an 18-month COBRA period ends can therefore leave someone outside the Part B enrollment window.
Write down two dates: the last day of current employment and the last day of active job-based group coverage. Confirm both with the employer or benefits administrator. Then ask Social Security or Medicare to confirm the Part B deadline that applies to your situation.
Part B and Part D follow different rules
Do not assume that every Medicare deadline is the same. A COBRA prescription benefit may be creditable drug coverage, which can affect Part D timing. The plan must tell you whether its drug coverage is creditable. Keep that notice.
Part B uses separate enrollment rules. Medicare warns that missing the applicable window can cause a coverage gap and a late-enrollment penalty that generally lasts as long as you have Part B. The exact result depends on your dates and whether another enrollment period or exception applies.
What to verify before you choose COBRA
Ask what COBRA covers, what it costs, when it ends, and whether dependent coverage changes if the Medicare-eligible person enrolls. If COBRA began before Medicare, Medicare says it will probably end when Medicare starts; confirm the actual plan terms before changing coverage.
For an independent explanation, California HICAP provides free, confidential Medicare counseling. An insurance agent can explain the Medicare products the agency represents, while Social Security and Medicare remain the sources for Part A and Part B enrollment decisions.
Three things to do next
- Write down the date current employment ended and the date job-based coverage ended.
- Ask the former employer or COBRA administrator how the coverage coordinates with Medicare.
- Confirm your Part B deadline with Social Security or Medicare before COBRA ends.
Check the official sources
- Medicare: COBRA coverage (opens in a new tab)
- Medicare: Working past 65 (opens in a new tab)
- Medicare: When coverage starts and Special Enrollment Periods (opens in a new tab)
- California HICAP counseling (opens in a new tab)
We prepare these explanations from the listed sources. This is general education, not a personalized recommendation. Confirm current rules and individual dates with the appropriate official source. Our editorial approach.