Medicare Open Enrollment 2026: When You Can Change Your Medicare Plan

Medicare open enrollment runs from October 15 through December 7 every year. During this seven-week window, anyone enrolled in Medicare can make changes to their coverage for the following year. Any changes you make take effect on January 1.

This period is officially called the Annual Enrollment Period (AEP), though most people know it as Medicare open enrollment. It applies to all Medicare beneficiaries, whether you have Original Medicare, a Medicare Advantage plan, or a standalone Part D prescription drug plan.

What You Can Do During Medicare Open Enrollment

The AEP is the broadest enrollment window Medicare offers. During these seven weeks, you can:

• Switch from Original Medicare to a Medicare Advantage plan
• Switch from Medicare Advantage back to Original Medicare
• Switch from one Medicare Advantage plan to another
• Join a Medicare Part D prescription drug plan
• Switch from one Part D plan to another
• Drop your Part D plan entirely (though be careful about the Part D late enrollment penalty if you lose creditable coverage)

If you switch from a Medicare Advantage plan back to Original Medicare, you can also enroll in a Medicare Supplement (Medigap) plan at the same time. Keep in mind that outside of your initial Medigap Open Enrollment Period, insurers in most states can use medical underwriting, which means approval is not guaranteed.

Medicare Open Enrollment vs. Other Enrollment Periods

The AEP is just one of several enrollment windows in Medicare. Each one serves a different purpose, and mixing them up can lead to missed deadlines or penalties.

Initial Enrollment Period (IEP)

This is your first chance to sign up for Medicare. It spans seven months: three months before the month you turn 65, your birthday month, and three months after. If you miss this window, you may face late enrollment penalties and coverage gaps.

Medicare Advantage Open Enrollment Period (MA OEP)

Runs January 1 through March 31 each year. This is specifically for people who are already in a Medicare Advantage plan. During the MA OEP, you can switch to a different MA plan or drop your MA plan and return to Original Medicare (and pick up a Part D plan). You cannot use this period to go from Original Medicare into a Medicare Advantage plan for the first time. For a full breakdown, see the guide to Medicare Advantage enrollment periods.

General Enrollment Period (GEP)

Also runs January 1 through March 31, but serves a completely different purpose. The GEP is for people who missed their Initial Enrollment Period and need to sign up for Medicare Part A or Part B. Coverage starts July 1, and late enrollment penalties may apply.

Special Enrollment Periods (SEPs)

Certain life events, like losing employer coverage, moving to a new state, or qualifying for Medicaid, can trigger a Special Enrollment Period that lets you make changes outside the normal windows. SEP rules and timelines vary depending on the qualifying event.

How to Prepare for Medicare Open Enrollment

The worst thing you can do during AEP is nothing. Plans change their benefits, costs, formularies, and provider networks every year. A plan that worked well for you this year might look very different next year.

Here's how to make the most of the window:

Review your Annual Notice of Change (ANOC). If you're in a Medicare Advantage or Part D plan, your insurer is required to send this document by September 30. It details every change to your plan for the coming year, from premium adjustments to dropped medications. The ANOC guide breaks down exactly what to look for.

Check your prescriptions against the formulary. Drug formularies shift every year. A medication that was Tier 2 this year could move to Tier 3 or get removed entirely. Log into Medicare.gov's Plan Finder tool and enter your current medications to compare costs across plans.

Verify your doctors are still in-network. If you have a Medicare Advantage plan, confirm that your primary care physician and any specialists you see regularly are still in the plan's network for next year.

Compare total costs, not just premiums. A plan with a $0 monthly premium might have higher copays, coinsurance, or a narrower network. Look at the full picture: premiums, deductibles, copays, coinsurance, and maximum out-of-pocket limits.

Don't wait until December 7. Procrastination is the most common AEP mistake. If you run into questions or need help comparing plans, a local Medicare insurance agent can walk you through your options at no cost to you.

What Happens If You Miss Open Enrollment?

If December 7 passes and you didn't make changes, your current coverage rolls over into the new year as-is (with whatever changes your plan made, per the ANOC). You're locked into that coverage until the next enrollment window opens.

There are a few exceptions:

• If you're in a Medicare Advantage plan, you can still use the MA Open Enrollment Period (January 1 - March 31) to make one plan change.
• If a qualifying life event occurs, you may be eligible for a Special Enrollment Period.
• If you have a 5-star rated plan, you can switch to it at any time during the year.

For most people, though, missing AEP means waiting a full year. That's 12 months on a plan that may no longer fit your needs or budget.

Common Mistakes During Medicare Open Enrollment

Assuming your plan hasn't changed. Even if you're happy with your current coverage, the plan itself may have changed its formulary, cost structure, or provider network. Always review the ANOC.

Ignoring Part D because you don't take medications. If you don't have creditable drug coverage from another source (like an employer plan), dropping or skipping Part D can trigger a permanent late enrollment penalty. The penalty compounds for every month you go without creditable coverage after your initial eligibility.

Only comparing premiums. Two plans with identical premiums can have wildly different out-of-pocket costs depending on what services you use. Factor in the deductible, copay structure, specialist costs, and maximum out-of-pocket cap.

Not factoring in upcoming health changes. If you have a surgery planned, a new diagnosis, or expect to start a new medication, your current plan may not be the best fit for next year. AEP is the time to plan ahead.

Do You Need to Do Anything If You're Happy With Your Plan?

You don't have to make a change during AEP. If you review your ANOC and your plan still meets your needs at a price you're comfortable with, doing nothing is a perfectly valid choice. Your coverage continues automatically.

That said, "happy with your plan" and "reviewed your plan" are two different things. The five minutes it takes to scan your ANOC could save you hundreds of dollars or prevent a surprise at the pharmacy counter in January.

Key Medicare Open Enrollment Dates

• September 30 - Deadline for plans to send your ANOC
• October 1 - Medicare.gov Plan Finder updates with next year's plan data
• October 15 - AEP opens, you can start making changes
• December 7 - AEP closes, last day to submit changes for January 1
• January 1 - New coverage takes effect