When and How to Change Your Medicare Plan

Yes, you can change your Medicare plan, but only during specific windows

You are not locked into your Medicare plan for life. You can switch plans, but Medicare sets strict dates when changes are allowed. Outside those dates, you cannot change unless you have a may have access to life event — a move, loss of coverage, or marriage, for example. The main annual window is the Annual Enrollment Period (AEP), which runs October 15 to December 7 each year. Changes made during AEP take effect January 1 of the following year.

If you miss AEP and have no may have access to event, you are stuck with your current plan until the next October. This is why knowing the important date matters: a missed important date costs you a full year of being in a plan you may not want.

Key Takeaways

The Annual Enrollment Period runs October 15 to December 7 each year, and changes take effect January 1.
If you have a may have access to life event — such as moving, losing employer coverage, or getting married — you can change plans outside AEP within 60 days of the event.
You can switch between Original Medicare and Medicare Advantage, or between different plans within the same category, but the rules and timing differ slightly.
If you miss a important date and have no may have access to event, you cannot change plans until the next October 15.

The Annual Enrollment Period: October 15 to December 7

This is the main window when anyone with Medicare can change plans, no questions asked. You can switch from Original Medicare to Medicare Advantage, from Medicare Advantage to Original Medicare, or from one plan to another within the same category. The change takes effect January 1, so you have about six weeks between when you enroll and when the new plan starts.

During AEP, you can also add or drop prescription drug coverage (Part D) if you are on Original Medicare, or switch between different Part D plans. If you are on Medicare Advantage, your drug coverage is bundled into the plan, so switching plans automatically changes your drug coverage too.

The important date is firm: if you enroll on December 7, you are in. If you enroll on December 8, you have missed the window. Mark October 15 on your calendar each year.

may have access to Life Events: The 60-Day Window

If you experience certain life changes, you can change plans outside the annual window. These are called may have access to events, and they give you 60 days from the date of the event to make a change. The event must have actually happened — you cannot change plans in anticipation of a move or a job loss.

Common may have access to events include: moving to a new state or county, losing employer-sponsored health coverage, getting married or divorced, becoming a U.S. citizen, or having a change in Medicaid status. If you are turning 65 and enrolling in Medicare for the first time, you also have a special window: you can enroll starting three months before the month you turn 65, and you have until three months after.

To use a may have access to event, you must report it to Medicare and provide proof. Contact Medicare at 1-800-MEDICARE or go to Medicare.gov to report the event and find out what documents you need. Do not wait — the 60-day clock starts the day the event happens, not the day you report it.

Original Medicare versus Medicare Advantage: Different Rules

If you are on Original Medicare (Parts A and B), you can add or drop a Medigap plan or Part D drug plan during AEP. You can also switch between different Medigap plans or different Part D plans. However, switching Medigap plans can trigger medical underwriting — the insurance company can ask about your health and deny you or charge more. This is why timing matters: if you are healthy now, switching is easier than if you wait until you have a new diagnosis.

If you are on Medicare Advantage, you have more flexibility during AEP. You can switch to a different Medicare Advantage plan, switch to Original Medicare, or switch to Original Medicare plus a Medigap plan. However, if you switch from Medicare Advantage to Original Medicare and want a Medigap plan, you may face medical underwriting unless you are within 63 days of first enrolling in Medicare Advantage.

The key difference: Original Medicare lets you add or drop supplemental coverage more easily, while Medicare Advantage bundles everything into one plan, so switching plans means switching your doctor network and drug formulary at the same time.

What Happens Between Now and January 1

Once you enroll in a new plan during AEP, your old plan ends on December 31 and your new plan starts on January 1. During this gap, you are still covered by your old plan. Do not cancel your old plan yourself — Medicare will handle the cancellation automatically.

Before January 1 arrives, review your new plan's documents. Check whether your doctors are in the network, whether your medications are on the formulary, and what your out-of-pocket costs will be. If you discover a problem after January 1, you have a small window to change again: if you enroll in a plan during AEP and then realize it does not cover your doctor or medication, you can switch to a different plan between January 1 and February 14 without penalty. This is called the Medicare Advantage Open Enrollment Period, and it applies only if you are switching between Medicare Advantage plans or from Medicare Advantage to Original Medicare.

Common Mistakes That Lock You Out

The most common mistake is missing the October 15 important date and having no may have access to event. If this happens, you are stuck until next October. There is no grace period, no exceptions for people who forgot, and no way to change the rule. Set a phone reminder for October 1 each year.

Another mistake is not reporting a may have access to event within 60 days. If you move in September but do not contact Medicare until November, you have missed the window. The 60 days is measured from the date the event happened, not from when you realize you need to change plans.

A third mistake is assuming your new plan will cover your doctor or medication without checking first. Plans change their networks and formularies every year. Just because your doctor was in your old plan does not mean they are in your new one. Before January 1, call your new plan and confirm coverage for your top three medications and your main doctor.

How to Change Your Plan

You have three ways to change: online at Medicare.gov, by phone at 1-800-MEDICARE, or in person at a local Social Security office. Online is fastest — you can compare plans side by side and enroll in minutes. The phone line has longer wait times but can walk you through the process if you are unsure.

When you enroll, you will need your Medicare number (on your Medicare card), your current plan information, and the name and number of the plan you want to switch to. If you are switching from Medicare Advantage to Original Medicare and want a Medigap plan, you will need to enroll in Original Medicare first, then contact a Medigap insurance company separately — Medicare does not sell Medigap plans.

After you enroll, you will receive a confirmation letter in the mail within two weeks. Keep this letter. If your new plan does not start on January 1 as expected, this letter is your proof of enrollment.

Frequently Asked Questions

What happens if I miss the October 15 important date?

You cannot change plans until October 15 of the following year, unless you have a may have access to life event such as moving, losing coverage, or getting married. If you have a may have access to event, you have 60 days from the date it happens to make a change. Otherwise, you are locked in for the full year.

Can I change plans more than once a year?

Only if you have multiple may have access to events. Each may have access to event gives you one 60-day window to change. If you move in March and get married in July, you have two separate 60-day windows. However, you can only enroll once per may have access to event — you cannot change plans twice in the same 60-day window.

If I switch to a new plan in December, when does it start?

January 1 of the following year. Your old plan covers you through December 31. Do not cancel your old plan yourself — Medicare will end it automatically. If you enroll between January 1 and February 14 in a Medicare Advantage plan and then change your mind, you can switch again without penalty during that same window.

Do I lose coverage if I switch plans?

No. Your old plan covers you until December 31, and your new plan starts January 1. There is no gap. However, if you switch from Medicare Advantage to Original Medicare, your doctor network changes when ready on January 1, so confirm your doctor is accepting new Original Medicare patients before the switch takes effect.

Can I switch back to my old plan if I do not like the new one?

Only during the Medicare Advantage Open Enrollment Period (January 1 to February 14) if you are switching between Medicare Advantage plans or from Medicare Advantage to Original Medicare. If you switched from Original Medicare to Medicare Advantage and want to go back, you must wait until October 15 unless you have a may have access to event.

This guide is for general information only and is not medical, financial, legal, or other professional advice. For decisions specific to your situation, consult a qualified professional. See our Editorial Policy.