Is Medicare Part B mandatory?

Part B covers doctor visits and outpatient care, and you can choose to turn it down or delay it. However, if you do not sign up when you are first eligible and you do not have other qualifying coverage, such as coverage from a current employer, you may owe a late enrollment penalty. That penalty is an amount added to your Part B premium, and it can last for as long as you have Part B. In 2026, the standard Part B premium is $202.90 per month. So while Part B is technically optional, skipping it without qualifying coverage can lead to a lasting higher cost.