You typically settle your Medicare coverage for the year in the fall during the annual open enrollment period. But that’s not your only time to review your plans.

In this week’s column, Phil Moeller, the author of Get What’s Yours for Medicare: Maximize Your Coverage, Minimize Your Costs and co-author of the updated edition of How to Get What’s Yours: The Revised Secrets to Maxing Out Your Social Security, explains the special window that’s open until March 31.

Got a question of your own about Medicare or Social Security? Send it to

What are the different Medicare Advantage enrollment periods?

Question: I am so confused about all of Medicare’s enrollment periods. Is there a separate enrollment period for Medicare Advantage plans?

Phil Moeller: Yes, there is, and you’re asking about it just in the nick of time!

From Jan. 1 through March 31, there is what’s called a Medicare Advantage Open Enrollment Period. It is only available to you if you already have a Medicare Advantage plan, which you would have signed up for during one of those other Medicare enrollment periods, including fall open enrollment and your initial enrollment period when you turn 65.

And if it makes you feel any better, you are not the only one who is confused by these different sign-up periods. So am I, and I wrote a book about Medicare!

If you have a Medicare Advantage plan, this open enrollment period lets you switch to a new Medicare Advantage plan or ditch Medicare Advantage entirely and use Original Medicare.

Most Medicare Advantage plans are bundled with Part D prescription drug coverage. So you can get a new Medicare Advantage plan with such coverage. Or, you can get a stand-alone Part D plan if you opt for Original Medicare, which includes Part A coverage for stays in hospitals and nursing homes, and Part B coverage for doctors, outpatient services, and durable medical equipment.

These changes normally will take effect in the month after you’ve elected new coverage.

Before you switch from Medicare Advantage to Original Medicare, you also should explore whether you can get a Medicare Supplement plan from a private insurer. Medigap plans help pay for claims that are not fully paid by Original Medicare. For example, Part B of original Medicare pays out only 80% of covered claims. 

The wrinkle here is that Medigap insurers in most states are free to raise rates for pre-existing medical conditions, or even decline to sell a policy at all to people who have been on any form of Medicare for more than six months. Here’s a helpful study about Medigap plans that includes a state-by-state rundown of coverage rules.

You are not the only one who is confused by these different sign-up periods. So am I!

If you have Original Medicare, the Medicare Advantage Open Enrollment Period is not for you. You can’t move into an Advantage plan or change drug plans. 

Based on questions from other readers, the value of this enrollment period is greatest if you discover during the first quarter of the year that a preferred doctor is not in your plan’s provider network or that one of the drugs you take is not in your plan’s formulary of covered medicines.

In one of those cases, having what is essentially a “do-over” period is a godsend. But don’t dawdle. The window closes on March 31.

For more information, check out Medicare’s Plan Finder tool, which can help you compare plans in your area, or call 800-633-4227.