MEDICARE ENROLLMENT GUIDE
Medicare Advantage Open Enrollment Period 2027: Rules and Next Steps
Understand whether you can make a change, what to check first, and when your new coverage would begin.
Who can use Medicare Advantage OEP?
This annual window is for people already in a Medicare Advantage plan, including plans with or without prescription drug coverage. It is different from fall Annual Enrollment, which runs October 15–December 7.
Having Original Medicare alone does not make you eligible for MA OEP. There is also a separate opportunity for people who joined Medicare Advantage during their Initial Enrollment Period: they can change plans or return to Original Medicare during the first three months they have Part A and Part B. Check Medicare’s enrollment rules.
What can—and can’t—you change?
| Your proposed change | Allowed? |
|---|---|
| Medicare Advantage → another Medicare Advantage plan, with or without drug coverage | Yes |
| Medicare Advantage → Original Medicare, with the option to join a stand-alone Part D plan | Yes |
| Original Medicare → Medicare Advantage | No, not through MA OEP |
| Original Medicare + Part D → a different stand-alone Part D plan | No, not through MA OEP |
A separate enrollment opportunity may permit a change outside these rules. See Medicare’s guide to Medicare Advantage.
When does the new coverage start?
The effective date is generally the first of the month after the plan receives your request. For example, a request received February 12, 2027 generally takes effect March 1. A March request generally takes effect April 1. Keep the confirmation and verify the effective date before using the new coverage. Medicare explains effective dates.
Check these four things before making your one change
- Providers: Ask both the plan and your providers about the exact plan, office location, and hospital you use. Record the answers.
- Prescriptions: Compare your medications, doses, pharmacy, coverage restrictions, and estimated annual costs using Medicare Plan Compare.
- Total costs: Review premiums, deductibles, copays, coinsurance, and the plan’s medical out-of-pocket limit. A low premium alone does not tell you what care will cost.
- Coverage coordination: If returning to Original Medicare, arrange your drug coverage and investigate Medigap availability before finalizing the change.
What if you miss March 31?
Missing the deadline does not automatically create another enrollment window. A qualifying event, such as moving or losing certain coverage, may give you a Special Enrollment Period. The permitted change and deadline depend on your circumstances. Check Medicare’s Special Enrollment Period guidance.
If no other enrollment opportunity applies, fall Annual Enrollment may be your next chance to change coverage. Contact Medicare at 1-800-MEDICARE (1-800-633-4227) to confirm your options rather than submitting a request under an enrollment period that does not apply.
Common questions about MA OEP
Can I change plans more than once during MA OEP?
You can use the Medicare Advantage Open Enrollment Period for one change. Another change would require a separate valid enrollment opportunity; do not assume you can switch back before March 31.
Can I change only my stand-alone Part D plan?
MA OEP does not let someone with Original Medicare switch stand-alone drug plans. A separate enrollment period must apply. If you leave Medicare Advantage for Original Medicare during MA OEP, you can join a stand-alone Part D plan as part of that transition.
Do I have to change my Medicare Advantage plan?
No. This is an opportunity to review your coverage, not a requirement to replace it. Compare your current plan with alternatives before deciding.
Does leaving Medicare Advantage guarantee a Medigap policy?
No. The right to leave Medicare Advantage and the right to buy Medigap without medical underwriting are different. Check your Medigap open enrollment, guaranteed-issue, trial-right, and state protections before making a change.
Enrollment guidance is based on the official Medicare sources linked throughout this article.