Some people may get Medicare Part A “premium-free,” but most people have to pay a monthly premium for Medicare Part B. Because Medicare Part B comes with a monthly premium, some people may choose not to sign up during their initial enrollment period if they are currently covered under an employer group plan (either their own or through their spouse’s employer).
If you are still working, you should check with your health benefits administrator to see how your insurance would work with Medicare.
If you delay enrollment in Medicare Part B because you already have current employer health coverage, you can sign up later during a Special Enrollment Period without paying a late penalty. You can enroll in Medicare Part B at any time that you are still covered by a group plan based on current employment. After your employer health coverage ends or your employment ends (whichever comes first), you have an eight-month special enrollment period to sign up for Part B without a late penalty.
Keep in mind that retiree coverage and COBRA are not considered health coverage based on current employment and would not qualify you for a special enrollment period. If you have COBRA after your employer coverage ends, you should not wait until your COBRA coverage ends to sign up for Medicare Part B. Your eight-month Part B special enrollment period begins immediately after your current employment or group plan ends (whichever comes first). This is regardless of whether you get COBRA.