Every January, millions of Medicare Advantage enrollees get a second chance to reconsider their coverage. The Medicare Advantage Open Enrollment Period runs from January 1 through March 31 each year, giving current MA plan members an opportunity to make changes they may have missed during the fall Annual Enrollment Period. If your plan’s network shrank, your copays increased, or your preferred doctor left the roster, this three-month window is your remedy. Knowing exactly what you can and cannot do during this period can save you significant money and frustration.
What the Medicare Advantage Open Enrollment Period Is
The Medicare Advantage Open Enrollment Period (MA OEP) is a federally mandated enrollment window available exclusively to people who are currently enrolled in a Medicare Advantage plan on January 1. It is separate from the Annual Enrollment Period (AEP), which runs October 15 through December 7 and is open to all Medicare beneficiaries. The MA OEP exists specifically so that MA enrollees can make one additional plan change at the start of the new coverage year.
CMS introduced the MA OEP in its current form starting in 2019, restoring a switching opportunity that had previously been eliminated. The intent was to give beneficiaries who discovered problems with their plan after January 1, whether due to benefit changes, network disruptions, or premium increases, a practical way to correct course without waiting until the following fall.
What Changes You Can Make
During the MA OEP, you have three options. First, you can switch from one Medicare Advantage plan to another Medicare Advantage plan available in your area. Second, you can drop your Medicare Advantage plan and return to Original Medicare (Parts A and B). Third, if you return to Original Medicare, you can also enroll in a standalone Medicare Part D prescription drug plan.
You can make only one change during the MA OEP. Once you complete a switch or disenrollment, the window closes for you even if March 31 has not arrived. Your new coverage takes effect the first of the month following your enrollment or disenrollment. For example, if you switch plans on February 10, your new plan begins March 1.
Who Is Eligible
The MA OEP is available to anyone enrolled in a Medicare Advantage plan as of January 1 of the current year. This includes MA-only plans and Medicare Advantage Prescription Drug (MAPD) plans. It does not matter when you originally enrolled in the plan or how long you have been a member. If you are in an MA plan on New Year’s Day, you qualify.
People enrolled in Original Medicare with a Medigap plan are not eligible for the MA OEP because they are not in a Medicare Advantage plan. Their enrollment changes are governed by different rules, including the Annual Enrollment Period for Part D and the Medigap Open Enrollment Period for supplemental coverage.
Why You Might Use the MA OEP
Several common scenarios make the MA OEP valuable. Your plan may have removed your primary care doctor or specialist from its network effective January 1. Your copays or coinsurance rates may have increased in the plan’s Annual Notice of Changes. A prescription you depend on may have moved to a higher cost tier or been dropped from the formulary entirely. Or you may have experienced the plan’s prior authorization process for the first time and decided the restrictions are unacceptable.
The MA OEP is also the right time to consider returning to Original Medicare if you want unrestricted provider access nationwide. Returning to Original Medicare gives you the freedom to see any Medicare-accepting doctor without network limitations. You would then want to explore whether you can purchase a Medigap policy like Plan G to cover the cost-sharing gaps in Original Medicare.
The Medigap Complication
Here is the critical detail many beneficiaries overlook. If you use the MA OEP to return to Original Medicare, you may want a Medigap policy to cover your out-of-pocket costs. However, in most states, Medigap insurers can apply medical underwriting when you apply outside your initial Medigap Open Enrollment Period. That means health conditions you developed while on your MA plan could result in higher premiums, coverage exclusions, or outright denial.
There is one important exception. If you are within your first 12 months on a Medicare Advantage plan, you have a federally guaranteed “trial right” to return to the Medigap plan you had before joining MA, or to purchase Medigap Plan A, B, C, F, K, or L without medical underwriting. This trial right is a powerful protection, but it applies only during that initial 12-month window.
Several states, including California, Connecticut, Massachusetts, Missouri, and New York, provide additional Medigap protections. These may include annual guaranteed-issue windows or birthday-rule provisions. Check your state insurance department or our healthcare policy guide for specifics.
MA OEP vs. Annual Enrollment Period
The Medicare Advantage Open Enrollment Period and the Annual Enrollment Period (AEP) serve different purposes. The AEP, running October 15 through December 7, is the primary window for all Medicare beneficiaries to make changes for the following year. You can switch between MA plans, switch between Original Medicare and MA, or change your Part D plan. Changes take effect January 1.
The MA OEP is a narrower, supplementary window available only to current MA enrollees. It allows one change in the first quarter of the year. Think of the AEP as your primary shopping period and the MA OEP as a correction opportunity if your January 1 coverage did not work out as expected.
How to Make Your Change
To switch MA plans, contact the new plan directly or call 1-800-MEDICARE (1-800-633-4227). You can also visit Medicare.gov to compare available plans in your area. To disenroll from MA and return to Original Medicare, contact your current plan or call Medicare directly. If you want a Part D plan after returning to Original Medicare, enroll through the Part D plan’s website or by calling Medicare.
Keep documentation of your disenrollment and new enrollment. Confirm effective dates in writing. If you are also applying for a Medigap policy, begin that process simultaneously so there is no gap between your MA disenrollment date and your Medigap effective date. An independent insurance broker who specializes in Medicare can coordinate this transition for you.
Frequently Asked Questions
Can I use the MA OEP if I just enrolled in Medicare Advantage during the AEP?
Yes. If your new MA plan took effect on January 1 and you are dissatisfied, you can use the MA OEP to switch to a different MA plan or return to Original Medicare. You are allowed one change during the January 1 through March 31 window.
Can I join Medicare Advantage during the MA OEP if I am on Original Medicare?
No. The MA OEP is exclusively for people already enrolled in a Medicare Advantage plan. If you are on Original Medicare and want to join MA, your next opportunity is the Annual Enrollment Period (October 15 through December 7), unless you qualify for a Special Enrollment Period.
What if I switch MA plans during the MA OEP and then want to switch again?
You are limited to one change during the MA OEP. Once you complete a switch, the window closes for you. Your next opportunity to change plans would be the Annual Enrollment Period in the fall or a qualifying Special Enrollment Period triggered by a life event such as a move.
Will my prescriptions be covered during the transition?
If you switch from one MAPD plan to another, your drug coverage transfers to the new plan on the effective date. If you return to Original Medicare, you will need a standalone Part D plan for prescription coverage. Enroll in Part D at the same time you disenroll from MA to avoid a coverage gap. Review formularies carefully to ensure your medications are covered under the new plan.
Using the MA OEP Strategically
The Medicare Advantage Open Enrollment Period is a valuable safety net, not a planning tool. Your best strategy is to make a well-researched choice during the Annual Enrollment Period each fall. But if January reveals that your plan is not meeting your needs, act quickly. Compare your options, evaluate whether returning to Original Medicare with a Medigap plan is feasible, and make your one change before March 31. For a comprehensive comparison of your two main paths, read our Medigap vs Medicare Advantage guide, and visit our healthcare costs resource for budgeting strategies.