What Is the Medicare Advantage Open Enrollment Period and Who Can Use It?

Already in a Medicare Advantage plan? The OEP runs Jan 1-Mar 31 and lets you switch plans or return to Original Medicare — here's exactly how it works.

Author: Lynsey Brennan, Licensed Medicare Advisor | Published October 06, 2026 Reading time: 6 min read

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Quick Answer

The Medicare Advantage Open Enrollment Period (OEP) runs January 1 through March 31 each year. If you're already enrolled in a Medicare Advantage plan, you can use it to switch to a different Medicare Advantage plan or drop your current plan and return to Original Medicare (Parts A and B). People who are still on Original Medicare cannot use the OEP to join a Medicare Advantage plan for the first time.

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Key Takeaways

• The Medicare Advantage OEP is only for people already enrolled in a Medicare Advantage plan — not for new Medicare enrollees.
• You can make one election during the OEP: switch MA plans, or go back to Original Medicare.
• If you return to Original Medicare during the OEP, you have a limited right to enroll in a standalone Part D drug plan.
• The OEP is separate from the Annual Enrollment Period (Oct 15-Dec 7) — see our full Medicare enrollment periods guide for how they differ.
• Medigap guaranteed issue rights after the OEP are limited — timing matters, especially in Florida.

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Table of Contents

1. What Is the Medicare Advantage OEP, Exactly? 2. Who Can — and Cannot — Use the OEP 3. What Changes You Can Make During the OEP 4. What About Part D Coverage? 5. Florida-Specific Considerations 6. OEP vs. Annual Enrollment Period: Key Differences 7. Should You Use the OEP? Honest Trade-Offs

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What Is the Medicare Advantage OEP, Exactly? {#what-is-the-medicare-advantage-oep}

The Medicare Advantage Open Enrollment Period is a three-month window — January 1 through March 31 — created specifically for people who realize their current Medicare Advantage plan isn't working the way they expected after the new plan year begins.

Think of it as a correction window. You made your plan choice during the fall Annual Enrollment Period, the new year started, and now you're actually using the plan. Maybe your preferred cardiologist isn't in-network. Maybe the copays are higher than you anticipated. The OEP gives you one chance to course-correct.

Any change you make during the OEP takes effect the first day of the month after your plan receives your enrollment request. So if you switch in February, your new coverage typically starts March 1.

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Who Can — and Cannot — Use the OEP {#who-can-and-cannot-use-the-oep}

Who CAN use it:

• Anyone enrolled in a Medicare Advantage plan (with or without drug coverage) on January 1 of that year.

Who CANNOT use it:

• People on Original Medicare (Parts A and B only) who want to join a Medicare Advantage plan for the first time — the OEP does not allow new MA enrollment.
• People who are not yet enrolled in Medicare at all.

This is one of the most common misconceptions I hear. A caller will say, "I missed the fall enrollment period — can I use the January OEP to get into an Advantage plan?" The answer is no. If you're starting from Original Medicare, you'd need to qualify for a Special Enrollment Period or wait for the next Annual Enrollment Period.

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What Changes You Can Make During the OEP {#what-changes-you-can-make-during-the-oep}

You get one election during the OEP. Your options are:

1. Switch from one Medicare Advantage plan to a different Medicare Advantage plan. This includes switching plan types — for example, from an HMO to a PPO — or from a plan with drug coverage (MAPD) to one without, or vice versa.

2. Drop your Medicare Advantage plan and return to Original Medicare (Parts A and B). If you do this, you can also enroll in a standalone Part D drug plan.

You cannot use the OEP to:

• Switch from Original Medicare to a Medicare Advantage plan
• Make changes to a standalone Part D plan if you're staying on Original Medicare
• Enroll in Medicare Supplement (Medigap) with guaranteed issue rights in most states (Florida has specific rules — see below)

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What About Part D Coverage? {#what-about-part-d-coverage}

If you return to Original Medicare during the OEP, you can enroll in a standalone Part D prescription drug plan at the same time. Your drug coverage would start the first of the following month.

A few 2026 Part D facts worth knowing:

• The annual out-of-pocket threshold for covered Part D drugs is $2,100 in 2026, per CMS CY 2026 Part D benefit parameters — meaning once you hit that amount, you pay no more for covered drugs the rest of the year.
• Covered insulin is capped at $35/month under Medicare Part D.

If you're switching from one Medicare Advantage plan with drug coverage to another, your new plan's drug formulary applies starting the effective date. Always check whether your specific medications are covered before switching.

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Florida-Specific Considerations {#florida-specific-considerations}

Florida has one of the highest Medicare Advantage enrollment rates in the country — 56.1% of Florida Medicare beneficiaries are in an Advantage plan, per CMS Medicare Monthly Enrollment, 2024. That's above the national average of approximately 54% (CMS, 2024). With that many Floridians in MA plans, the OEP is a genuinely relevant window for a large portion of the state.

One critical Florida angle: if you drop your Medicare Advantage plan during the OEP and return to Original Medicare, you may want Medigap coverage to help cover costs like the $283 Part B deductible and Part A coinsurance (CMS, November 2025). But here's the honest reality — Florida follows federal Medigap guaranteed issue rules, which means insurers can generally use medical underwriting if you're outside a protected enrollment window. You may face higher premiums or potential denial based on health status.

The OEP itself does not automatically grant you Medigap guaranteed issue rights in Florida. If you're considering this move, talk to a licensed Medicare advisor before you submit any enrollment changes. Timing and sequencing matter.

For more data on Medicare plan options in your area, see our Florida Medicare data page.

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OEP vs. Annual Enrollment Period: Key Differences {#oep-vs-annual-enrollment-period}

| | Annual Enrollment Period | Medicare Advantage OEP | |---|---|---| | Dates | Oct 15 - Dec 7 | Jan 1 - Mar 31 | | Who can use it | Almost anyone on Medicare | Only current MA enrollees | | Can join MA for first time? | Yes | No | | Number of changes allowed | Multiple | One | | Coverage start | January 1 | First of following month |

The AEP is your main annual opportunity to make sweeping changes. The OEP is a narrower fix-it window. For a full breakdown, visit our Medicare enrollment periods guide.

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Should You Use the OEP? Honest Trade-Offs {#should-you-use-the-oep}

Medicare Advantage plans can offer benefits that Original Medicare doesn't cover — dental, vision, hearing, and fitness programs are common examples. The 2026 in-network out-of-pocket maximum for MA plans is capped at $9,350 (CMS, 2025), which can provide a ceiling on your costs.

But MA plans also come with trade-offs: provider networks, referral requirements, and prior authorization rules that Original Medicare doesn't have. Our Medicare Advantage vs. Supplement comparison walks through those differences honestly.

If your current MA plan's network or formulary isn't working for you in early 2026, the OEP may be worth using. If you're relatively satisfied and just want to explore options, it may make more sense to wait for the fall AEP when you can compare all available Medicare plans 2026 side by side using our plan comparison tool.

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Frequently Asked Questions

Q: Can I use the Medicare Advantage OEP to switch to a Medicare Supplement plan? A: Not directly. The OEP lets you drop your MA plan and return to Original Medicare, but enrolling in a Medigap plan is a separate step. Depending on your state and health history, you may or may not qualify for a Medigap plan without medical underwriting — speak with a licensed Medicare advisor before making any changes.

Q: How many times can I change plans during the OEP? A: You're allowed one election change during the Medicare Advantage OEP. Once you make that change, the OEP window is closed to you for that calendar year.

Q: Does the OEP apply to Medicare Supplement (Medigap) plans? A: No. The Medicare Advantage OEP applies only to Medicare Advantage enrollment. Medigap plans have their own separate enrollment rules and do not have an OEP equivalent. See our Medicare Supplement guide for details.

Q: If I switch MA plans during the OEP, when does my new coverage start? A: Your new coverage typically starts on the first day of the month after your new plan receives your completed enrollment request. For example, a request received in February would generally result in March 1 coverage.

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The Bottom Line

The Medicare Advantage OEP is a focused, one-time opportunity each January through March to correct a plan choice that isn't working for you — but it's only available to people already enrolled in a Medicare Advantage plan. If you're unsure whether switching makes sense, or you want to weigh MA against Original Medicare plus a Medigap policy, getting a second set of eyes on your situation can help. I offer a free Medicare plan review for Florida residents — no pressure, just a straight conversation about your options. You can also reach me directly at 561-247-0678.

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Sources

• CMS Medicare Monthly Enrollment, 2024 — Florida and national Medicare Advantage enrollment figures
• CMS, November 2025 — 2026 Part B premium ($202.90/month) and Part B deductible ($283)
• CMS CY 2026 Part D Benefit Parameters — Annual out-of-pocket threshold ($2,100); insulin cap ($35/month)
• CMS, 2025 — 2026 Medicare Advantage in-network out-of-pocket maximum cap ($9,350)
• CMS Medicare Advantage OEP regulations — Election period rules and eligible changes

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This article is for educational purposes and is not affiliated with or endorsed by the federal Medicare program or any government agency. HealthPlan Connect is a private, licensed Medicare advisory service. FL License #G007269.