Yes, you can switch from the Health Insurance Marketplace to Medicare when you are eligible, but it is incredibly important to do so in a planned and timely manner to avoid complications, issues, and late penalties.
What is the Health Insurance Marketplace?
The Health Insurance Marketplace helps people without healthcare coverage find and enroll in a plan. There are a variety of benefits in doing so, including tax credits and other ways of providing extra benefits and ways of making it more affordable.
When You Should Make the Switch
You are not required to end your Marketplace plan as soon as you become eligible for Medicare. However, the best time to cancel it and transition to Medicare is as soon as possible. For most people, this begins at age 65. However, the timing of this process can be a bit tricky.

Canceling Your Marketplace Plan
The cancellation process depends on the number of people on the contract. If you want to cancel it for everyone on the plan, you can contact your provider and have it done the same day, or set it for a day in advance.
If you have multiple people on the contract but only want to cancel it for some, all will first have to be unenrolled. Once again, this can either occur the day of or be set on a future date. The individual(s) who originally intended to leave the plan may now enroll elsewhere (in this case, Medicare). The people who wish to remain will have a Special Enrollment Period (SEP) and can re-enroll within 7 months of cancellation.
Enrolling in Medicare
It is incredibly important that you cancel your marketplace plan before your Medicare coverage starts. If you keep your marketplace plan with Part A, you will have to pay the full price for it.
The three months before, the month of, and 3 months after your 65th birthday are known as your Initial Enrollment Period (IEP). This is the absolute best time to enroll in Medicare, and your coverage will come into effect beginning at the start of the following year.
You must time, then, your marketplace cancellation, both to avoid the overlap and a gap in coverage. Because marketplace coverage can be canceled very quickly, it is best to wait as close as possible to the date Medicare comes into effect. Once the time comes, log into your marketplace account and follow through with the cancellation by clicking the “terminate coverage” button, or calling your plan provider. Make sure you know who you’re canceling for if multiple people are on the plan.