Short Answer: There are three main times you can enroll in Medicare Advantage (Part C), the same as with Original Medicare: You can sign up during your Initial Enrollment Period (a seven-month period beginning three months before your 65th birthday and ending three months after your birthday month); during a later eight-month Special Enrollment Period, if you're currently working and get health insurance from your job or other specific circumstances apply; or during Medicare's annual open enrollment period, which runs from October 15 to December 7.
Most people enroll in Medicare Advantage (Part C) when they first become eligible for Medicare, during their Initial Enrollment Period. This is a seven-month period covering the three months before the month of your 65th birthday, your birthday month itself, and the three months following your birthday month.
Another popular time to enroll is during the Annual Election Period (AEP), which runs from October 15 to December 7 each year. If you already have Medicare Advantage, you can also switch plans during this period or elect to go with Original Medicare instead.
If you do nothing during the Annual Election Period, your current health coverage under Medicare will be automatically renewed, as long as it continues to be available.
If you (or your spouse) are still working and have delayed signing up for Medicare Part B because you still get health coverage from a current employer, you can sign up for a Medicare Advantage plan (or Original Medicare, for that matter), when you stop working and that health coverage ends during what's known as a Special Enrollment Period (SEP). The SEP lasts for two months after the month your work coverage ends.
There are a few other circumstances when you can sign up for Medicare Advantage during a Special Enrollment Period. They are:
- Your current plan is discontinuing coverage in your area, or you move out of the service area.
- You have Original Medicare and Medicare SELECT (a type of Medigap policy a Medigap policy that limits your coverage to a specific network of hospitals and, in some cases, doctors), and you move out of the Medicare SELECT plan’s service area.
- You dropped your Medicare Supplement (Medigap) plan for a Medicare Advantage plan for the first time, and you want to switch back within the first year of coverage.
- Your insurance company goes bankrupt, or otherwise your coverage ends through no fault of your own.
- Your insurance company hasn’t followed the rules, or has misled you.
From December 8 to November 30 (the following year), you also have a one-time opportunity to enroll in a Medicare Advantage plan that is rated 5-stars by the Centers for Medicare & Medicaid Services (CMS). You may only use this SEP if there is a 5-star plan in your area.
For a complete list of SEPs, check out the official U.S. Government site for Medicare here.