You can switch Medicare Advantage plans during specific windows each year, and the rules depend on whether you're new to Medicare or already enrolled

Medicare Advantage plans lock you in for a year, but you get three main chances to switch: the Annual Enrollment Period (October 15 to December 7), the Medicare Advantage Open Enrollment Period (January 1 to March 31), and certain life events that happen outside those windows. The first window is the longest and the one most people use. The second window is shorter but exists specifically so people can change their minds after the holidays. Life events — like moving out of your plan's service area, losing employer coverage, or getting married — let you switch anytime they occur, though you usually have 60 days to act.

The catch is that you can only switch once during each window. If you change plans in October, you cannot change again until January 1. And if you switch during the January-March window, you're locked in until October. Knowing which window applies to your situation and what counts as a life event saves you from being stuck in a plan you don't want.

Key Takeaways

  • The Annual Enrollment Period (October 15 to December 7) is when most people switch plans, and changes take effect January 1.
  • The Medicare Advantage Open Enrollment Period (January 1 to March 31) lets you switch once if you change your mind after the holidays, with changes effective the first of the following month.
  • Life events like moving, losing coverage, or getting married let you switch outside the regular windows, but you must report the event to Medicare within 60 days.
  • You can only switch once per enrollment window, so choosing carefully matters because you're locked in until the next window opens.
  • Your new plan's coverage starts on the first day of the month after Medicare processes your switch, which usually takes one to two weeks.

The Annual Enrollment Period: October 15 to December 7

This is the main switching window and the one you should mark on your calendar. It runs from October 15 through December 7 each year. Any plan change you make during this window takes effect on January 1 of the following year. This gives you time to review your current plan's costs and coverage, compare other plans available in your area, and switch before the new year.

You switch by calling Medicare at 1-800-MEDICARE, visiting Medicare.gov, or working with a licensed insurance agent. Medicare will ask you to confirm your current plan and tell them which new plan you want. The process takes about 15 minutes on the phone. After you switch, Medicare sends you a confirmation letter within one week, and your new plan sends you a welcome packet with your member ID card and plan details.

If you miss this window, you cannot switch again until January 1 — unless a life event happens that qualifies you for a Special Enrollment Period. Many people miss the important date because they assume they can switch anytime, so set a reminder in early October.

The Medicare Advantage Open Enrollment Period: January 1 to March 31

This three-month window exists because people often realize after the holidays that they chose the wrong plan. Maybe they got a bill they didn't expect, or their doctor left the network, or they straightforward changed their mind. During this period, you can switch to a different Medicare Advantage plan or switch to Original Medicare plus a Medigap or Part D plan.

The rules are stricter than the October window: you can only make one change, and the change takes effect on the first day of the month after Medicare processes it. If you switch on January 15, your new coverage starts February 1. If you switch on March 20, your new coverage starts April 1. This means if you wait until late March, you could be in your new plan for only a few months before the October enrollment period arrives.

You switch the same way — by calling Medicare, going online, or using an agent. But once you make a change during this window, you cannot change again until October 15, even if you realize the new plan is also wrong. This is why it's worth taking time to compare before you switch.

Life Events That Let You Switch Anytime

Certain changes in your life let you switch Medicare Advantage plans outside the regular enrollment periods. These are called may have access to Life Events, and Medicare gives you 60 days from the date the event happens to make a change. The most common ones are moving out of your plan's service area, losing employer-sponsored health coverage, getting married or divorced, and becoming may be able to access for Medicaid or losing Medicaid.

If you move and your current plan no longer serves your new address, you can switch when ready. If you retire and lose your employer's health plan, you have 60 days to switch. If you get married, you have 60 days to switch (though your spouse cannot use your life event — they have their own enrollment periods). If you become newly may be able to access for Medicaid, you can switch anytime during the month you become may be able to access and the two months after.

To use a life event, you must report it to Medicare within 60 days. Call 1-800-MEDICARE and tell them what happened. They will ask for proof — a lease or utility bill for a move, a termination letter from your employer, a marriage certificate, or a Medicaid approval letter. Once Medicare confirms the event, they will give you a Special Enrollment Period, usually good for two months, during which you can switch once.

What Happens When Your Switch Takes Effect

After you switch, your old plan coverage ends on the last day of the month before your new coverage starts. If your new plan starts January 1, your old plan ends December 31. If your new plan starts April 1, your old plan ends March 31. This means there is no gap in coverage — you are always covered by one plan or the other.

Your new plan sends you a member ID card, usually within one to two weeks. Use your old card until the new one arrives. If you need care before the new card comes, call the new plan's customer service number (on the welcome letter) and give them your name and date of birth — they can look you up in their system. Pharmacies and doctors can also verify your coverage by calling the plan directly.

Your prescriptions may not transfer automatically. If you're on medications, contact your new plan's pharmacy department before your coverage starts and ask them to transfer your prescriptions from your old plan's pharmacy. Some plans do this automatically; others require you to ask. Doing this early prevents gaps in your medication supply.

Switching from Medicare Advantage to Original Medicare

You can switch from a Medicare Advantage plan to Original Medicare (Medicare Parts A and B) during the Annual Enrollment Period or the Medicare Advantage Open Enrollment Period. You can also switch if a life event qualifies you for a Special Enrollment Period. However, if you switch to Original Medicare outside of these windows without a may have access to life event, Medicare will not process the switch.

When you switch to Original Medicare, you lose your Medicare Advantage coverage and your prescription drug coverage. If you want prescription coverage, you must join a standalone Part D plan at the same time. If you want coverage for things Original Medicare doesn't pay for — like copays and coinsurance — you should join a Medigap plan. You can join a Medigap plan without a waiting period if you switch from Medicare Advantage within 63 days of losing that coverage.

This switch is permanent for that year. You cannot switch back to Medicare Advantage until the next October enrollment period. So if you switch to Original Medicare in November, you're in Original Medicare for the rest of that year and all of the next year until October arrives.

Common Mistakes to Avoid When Switching

The biggest mistake is waiting until December to switch and then discovering your new plan doesn't cover your doctor or pharmacy. Compare plans in September and October, when you have time to call the plan and verify that your doctors are in-network and your medications are covered. Do not assume a doctor is in-network just because they were in your old plan — networks change every year.

Another mistake is switching during the January-March window without realizing you cannot switch again until October. People do this thinking they can always change their mind, then get stuck in a plan they don't like for nine months. Use the January window only if you're certain about your new choice.

A third mistake is not reporting a life event to Medicare within 60 days. If you move in February but don't call Medicare until April, you've lost your Special Enrollment Period and cannot switch until October. Keep documentation of life events — a lease, a termination letter, a marriage certificate — and call Medicare as soon as the event happens.

Finally, do not assume your new plan's coverage starts when ready. It always starts on the first of a month, and there's usually a one to two-week processing delay. If you need care in the gap between when you switch and when your new coverage starts, use your old plan. After your new coverage starts, use your new plan.

Frequently Asked Questions

Can I switch plans if I'm unhappy with my current plan mid-year?

Not unless a life event qualifies you for a Special Enrollment Period. Otherwise, you must wait for the Annual Enrollment Period (October 15 to December 7) or the Medicare Advantage Open Enrollment Period (January 1 to March 31). If you're unhappy because your doctor left the network or you moved, those are life events — call Medicare at 1-800-MEDICARE to report them.

What counts as a life event that lets me switch outside the regular windows?

Moving out of your plan's service area, losing employer health coverage, getting married or divorced, becoming may be able to access for Medicaid, and losing Medicaid all may have access to. Death of a spouse, becoming a U.S. citizen, and court orders related to custody also count. You have 60 days from the date the event happens to report it to Medicare and switch plans.

If I switch in January, when does my new coverage start?

Your new coverage starts on the first day of the month after Medicare processes your switch. Processing usually takes one to two weeks. If you switch January 10, your new coverage likely starts February 1. If you switch March 25, your new coverage likely starts May 1 because of the processing delay.

Can I switch back to my old plan if I don't like my new one?

Only if you switch during the Medicare Advantage Open Enrollment Period (January 1 to March 31) and you haven't already made a change that year. If you switched in October and then switched again in January, you cannot switch a third time until October. If you switched in January, you cannot switch again until October.

What happens to my prescriptions when I switch plans?

Your old plan's pharmacy will not automatically transfer your prescriptions to your new plan's pharmacy. Contact your new plan's pharmacy department before your coverage starts and ask them to transfer your prescriptions. Some plans do this automatically; others require you to request it. This prevents gaps in your medication supply.