You can only enroll at certain times:

• When you first sign up for Part B
• During Fall Open Enrollment (October 15 to December 7)

You cannot join an MSA:

• During the Medicare Advantage Disenrollment Period -- MADP (January 1 to February 14 of every year);
• If you have any other types of health insurance, including Medicaid, Veterans benefits, Federal Employee Health Benefits, or many kinds of employer or retiree insurance. (You cannot have any employer/retiree coverage that would pay during your MSA deductible. Call your employee benefits manager to find out if and how your employer or retiree insurance would work with a Medicare MSA plan.)

If you already have a Medigap—a Medicare supplemental insurance plan—you can keep it with an MSA, but the Medigap will cost you money without providing additional coverage. You cannot buy a Medigap if you are in an MSA.

If you are considering joining an MSA, make sure you speak to a representative, get information in writing, and fully understand the plan’s offerings before making a commitment.