Generally, you do not need to sign up for Medicare when you turn 65 if you are still working and have health insurance coverage based on your or your spouse’s active employment, and the employer has more than 20 employees. Most often, in this situation, you are entitled to a Special Enrollment Period when your employment or insurance ends, whichever happens first. During your Special Enrollment Period, you have eight months to enroll in Medicare A & B without incurring a penalty. Most people, sign up for A & B immediately so there is no gap in their coverage.
Signing Up for Medicare
To sign up during your Special Enrollment Period, you are required to enroll through the Social Security Administration website, http://www.ssa.gov, unless you are already have Medicare Part A. If you already have Medicare Part A, you just need to sign up for Medicare Part B.
Health Savings Account (HSA) Considerations
When you are enrolling in Medicare Part A and you are older than 65, Social Security will backdate your Medicare Part A effective date six months from when you apply for it. Currently, you are not allowed to make contributions to your HSA if you are enrolled in any part of Medicare. Therefore, you could have tax implications if your Medicare Part A is backdated to a time when you were making HSA contributions.
Once you sign up for Medicare Parts A & B, you have two choices on how to receive your Medicare: