Signing Up for Medicare When You're Still Covered by an Employer's Health Plan

Beneficiaries have a seven-month window to enroll in Part A and Part B of Medicare. The Initial Enrollment period begins three months before the month one turns 65 and ends three months after the birthday month.

Enrollment in Medicare can be done online at or visit the local Social Security office (once they are out of Lockdown), even if you're not ready to receive Social Security retirement benefits yet. Go to the Apply for Benefits page to sign up for retirement or Medicare benefits. Also see the SSA's Checklist For Online Medicare Application for a list of information needed to complete the application. (Those who are already receiving Social Security benefits are automatically enrolled in Medicare at age 65. They will receive a Medicare card in the mail three months before their coverage starts, which is the first day of the month of their 65th birthday.)

The timing of the enrollment will determine when coverage kicks in. If you sign up before the month you turn 65, your coverage will take effect on the first day of your birthday month-October 1, in this case. (If your birthday had been on the first of the month, your coverage would take effect the first day of the previous month, or September 1.)

Sign up in the month you turn 65 and your coverage will take effect on the first day of the next month. If you sign up one month after your birthday month, your coverage will take effect two months after enrollment. Enroll two or three months after your birthday month and the coverage will take effect three months after the month you sign up. See When Will My Coverage Start? at for a helpful table illustrating the time frames.

Previously you wouldn't be able to sign up for Part B online if you delayed coverage past age 65. You would have had to either mail your application or visit a Social Security office to provide evidence that you had coverage from your employer and shouldn't be subject to a late-enrollment penalty. Due to the closure of the Social Security offices due to Covid19, some of these procedures have changed. See the next article below for the latest information.

You will need to enroll in Part B within eight months of losing your coverage at work when you leave your job (or when you lose coverage through a spouse's employer). If you enroll while you're still on your employer's group health plan or during the first full month when you are no longer on the plan, your coverage can either begin on the first day of the month you enroll or start on the first day of any of the following three months. If you enroll during the remaining seven months of this "special enrollment period" after you leave your job, then your Part B coverage begins on the first day of the following month.

It is important to remember that retiree coverage (or Cobra) is not coverage as an Active Employee. Failing to sign up by the end of the eight-month special enrollment period can trigger a permanent late-enrollment penalty, which is 10% of the current Part B premium for every full year delayed. It may also force you to enroll in Part B during the General Enrollment Period for Part B, which is January through March for a July effective. This may leave you with many months without coverage.

Also remember that Cobra coverage, or Retiree plans (regardless of the size of the employer) are always secondary to Medicare! Make sure that Medicare coverage is in place to reduce exposure!