Medicare Advantage Open Enrollment Period: The January 1 to March 31 Do-Over, Explained for Florida
One change, between January 1 and March 31. That's the whole Medicare Advantage Open Enrollment Period. If you're in a Medicare Advantage plan on New Year's Day 2027, federal rules in 42 CFR 422.62(a)(3) let you switch to a different Medicare Advantage plan or leave for Original Medicare, once, and the change takes effect the first of the month after the plan gets your request.
Fall Open Enrollment is running right now and closes December 7. Plenty of Floridians will pick a plan in the next five weeks, see how it actually works in January (which doctors take it, what the pharmacy charges), and want a do-over. This is the window that gives them one. It's also narrower than people think, and in Florida the hard part isn't the Medicare rule. It's what happens to Medigap if you leave Medicare Advantage after your first year.
Source: 42 CFR 422.62(a)(3); 42 CFR 422.68(c); 42 CFR 423.38(e); CMS, Medicare Monthly Enrollment, Florida, July 2026. Day count computed.
Who can use it, and who can't
Only people who are already enrolled in a Medicare Advantage plan. That includes plans with drug coverage and plans without it. If you have Original Medicare, with or without a Medigap policy and a drug plan, this window does nothing for you. You can't use it to join Medicare Advantage, and you can't use it to swap one stand-alone drug plan for another.
That second point is easy to miss. Say someone on Original Medicare picks a drug plan in November, finds out in January that a prescription costs more than expected, and assumes there's a January fix. Under CMS enrollment and disenrollment guidance, CY 2027, sec. 30.4, there isn't one in this window. They'd need a Special Enrollment Period or wait for next fall.
A few smaller groups are also left out. CMS says people in a Medicare Medical Savings Account plan, a cost plan or PACE can't make enrollment changes using it. People living in a nursing home or similar facility have their own open enrollment period with no one-change limit under 42 CFR 422.62(a)(4), so they don't need this one.
| Your situation on January 1 | Allowed? | What it looks like |
|---|---|---|
| Medicare Advantage plan with drug coverage | Yes | Switch to another Medicare Advantage plan, with or without drug coverage |
| Medicare Advantage plan with drug coverage | Yes | Drop it for Original Medicare and join a stand-alone Part D plan at the same time |
| Medicare Advantage plan without drug coverage | Yes | Switch to a Medicare Advantage plan that includes drug coverage, or return to Original Medicare and add Part D |
| Original Medicare (with or without Medigap) | No | Can't join a Medicare Advantage plan in this window |
| Original Medicare plus a stand-alone drug plan | No | Can't switch drug plans or join one in this window |
| Medicare MSA plan, cost plan or PACE | No | CMS excludes these from the MA Open Enrollment Period |
Source: CMS enrollment and disenrollment guidance, CY 2027, sec. 30.4; Medicare & You 2027, pp. 13 and 75; 42 CFR 423.38(e).
The one-change rule, read carefully
The regulation says you may make an election "once during the first 3 months of the year." The handbook puts it more bluntly: you can only make one change during this period. Once that change takes effect, the window is used up for the year.
There's one detail that softens it. CMS's guidance says that in most situations you can submit more than one enrollment request before the first one takes effect, and the last request the plan receives is the one that counts. So if you send a switch request on February 3 and realize on February 10 that you picked wrong, you may still be able to fix it before March 1. After March 1, you're done until fall, unless a Special Enrollment Period applies.
The one-change limit doesn't apply to changes made during fall Open Enrollment or under a Special Enrollment Period. If you move from Tampa to Jacksonville in February, for example, the moving SEP gives you a separate chance that doesn't count against this one. My Special Enrollment Periods post lists the common ones.
When the change takes effect
Coverage changes on the first day of the month after the plan receives your request (42 CFR 422.68(c)). Not the day you call. Not January 1. Here is how that plays out in 2027.
| Plan gets your request | New coverage starts | Old coverage runs through |
|---|---|---|
| Any day in January 2027 | February 1, 2027 | January 31, 2027 |
| Any day in February 2027 | March 1, 2027 | February 28, 2027 |
| Any day in March 2027 (through the 31st) | April 1, 2027 | March 31, 2027 |
| April 1, 2027 or later | Not allowed under this window | You keep your plan unless an SEP applies |
Source: 42 CFR 422.68(c); CMS guidance CY 2027, secs. 30.4 and 30.7; Medicare.gov, Joining a plan. Dates computed.
Two practical notes. First, CMS counts the date the plan receives your request, not the date you send it. A request the plan gets on March 31 counts; one mailed on March 31 that arrives April 2 falls outside the window. Use the phone, the plan's website or Medicare.gov if you're close to the end. Second, if you have a surgery, a new prescription or a specialist visit coming up, the month you pick matters. Whatever happens on February 27 is billed under the old plan if your change starts March 1.
MA Open Enrollment vs. fall Open Enrollment vs. the General Enrollment Period
Three Medicare windows get confused because two of them share the same dates. Fall Open Enrollment (October 15 to December 7) is the big one: anyone with Medicare can make almost any plan change, as many times as they want before the deadline, and everything starts January 1. The General Enrollment Period (January 1 to March 31) has the same calendar as the MA Open Enrollment Period but is about something else entirely: signing up for Part B, or premium Part A, if you missed your first chance. I covered it in the General Enrollment Period post.
| Fall Open Enrollment | MA Open Enrollment Period | General Enrollment Period | |
|---|---|---|---|
| Dates | Oct 15 to Dec 7 (2026: now) | Jan 1 to Mar 31, 2027; also first 3 months of Medicare for new MA enrollees | Jan 1 to Mar 31, 2027 |
| Who | Anyone with Medicare | Only people already in a Medicare Advantage plan | People who missed their Initial Enrollment Period and have no SEP |
| What changes | Join, switch or drop Medicare Advantage or Part D; move between Original Medicare and Medicare Advantage | One change: another Medicare Advantage plan, or Original Medicare plus optional Part D | Sign up for Part B (and premium Part A) |
| How many changes | No limit before Dec 7; the last one counts | One | Not a plan change |
| Takes effect | January 1, 2027 | First of the month after the plan gets the request | First of the month after you sign up |
| Rule | 42 CFR 422.62(a)(2) | 42 CFR 422.62(a)(3) | 42 CFR 407.15; 406.21(c) |
Source: 42 CFR 422.62; 42 CFR 422.68; Medicare.gov, When does Medicare coverage start; Medicare & You 2027, pp. 13, 74-75.
If you get Part B for the first time during the General Enrollment Period, Medicare & You says you then have 2 months after adding Part B to join a Medicare Advantage plan. That's a separate path from the one-change window, and it's for people who aren't in Medicare Advantage yet. The national 2027 changes for fall Open Enrollment, which apply in Florida too, are in my 2027 Open Enrollment post.
New to Medicare: your own three-month version
The window isn't only in January. Under 42 CFR 422.62(a)(3)(ii), someone new to Medicare who is enrolled in a Medicare Advantage plan gets one change during the period that starts the month they're entitled to both Part A and Part B and ends on the last day of the third month.
Example, hypothetical: say your Part A and Part B both start July 1, 2027, and your Medicare Advantage plan starts the same day. Your personal window runs July 1 through September 30, 2027. You can make one switch to another Medicare Advantage plan or go back to Original Medicare and add Part D, with the change starting the first of the following month. CMS gives a similar example in section 30.4 of its guidance, and it works the same way if you delayed Part B because you were still working: the clock starts when you have both parts.
Picking a plan at 65 often happens on a deadline, sometimes in the middle of retiring or moving. This is the built-in second look. Note the date in your calendar the day your card arrives.
Leaving Medicare Advantage in Florida: the Medigap question
The Medicare rule lets you go back to Original Medicare. It doesn't guarantee you can buy a Medigap (Medicare Supplement) policy to go with it, and without one you pay Original Medicare's deductibles and coinsurance (usually 20% of the Medicare-approved amount for Part B services) with no yearly out-of-pocket limit, per Medicare & You. You also can't hold Medigap and Medicare Advantage at the same time, per Medicare.gov, and Medicare & You says it's illegal for anyone to sell you a Medigap policy while you're in Medicare Advantage unless you're switching back to Original Medicare.
Whether an insurer has to accept you depends on whether you have a guaranteed-issue right. In Florida, the ones that matter here are the federal "trial rights," which Florida writes into its own rule at F.A.C. 69O-156.0095:
- Joined Medicare Advantage when you first got Part A at 65. If you leave no later than 12 months after the plan's start date, you can buy any Medicare Supplement policy offered by any issuer, without medical underwriting (rule paragraphs (2)(f) and (5)(c)).
- Dropped a Medigap policy to try Medicare Advantage for the first time. If you leave within the first 12 months, you can get the same policy back if the same company still sells it, or certain other standardized plans if not (paragraphs (2)(e) and (5)(b)).
For a voluntary move back, the Florida rule's guaranteed-issue window starts 60 days before the date your Medicare Advantage coverage ends and runs to 63 days after it.
Outside those trial rights, Florida doesn't give you an annual do-over. Florida's Medigap statute, section 627.6741, guarantees issue during your 6-month Medigap open enrollment and for 2 months after group coverage ends. There's no birthday or anniversary rule. If you've been in Medicare Advantage for three years and leave during the MA Open Enrollment Period, CMS's Choosing a Medigap Policy guide is plain about it: there's no guarantee an insurance company will sell you a policy if you don't meet its medical underwriting requirements. The details are in my Florida Medigap rules post, and the plan types are on our Medicare Supplement insurance in Florida page.
| Your history | Can leave Jan 1 to Mar 31? | Medigap without underwriting? |
|---|---|---|
| Joined Medicare Advantage at 65 when first eligible for Part A; plan started less than 12 months ago | Yes | Yes: trial right, any Medicare Supplement policy from any issuer (69O-156.0095(2)(f)) |
| Dropped Medigap to try Medicare Advantage for the first time; less than 12 months in | Yes | Yes: trial right, old policy back if still sold, otherwise certain standardized plans (69O-156.0095(2)(e)) |
| In Medicare Advantage more than 12 months, no other qualifying event | Yes | Generally no: insurers may use medical underwriting |
| Medicare Advantage plan leaving your area or ending its contract | Usually through an SEP instead | Yes, under a separate guaranteed-issue situation (CMS Medigap guide) |
Source: F.A.C. 69O-156.0095; s. 627.6741, F.S.; CMS, Choosing a Medigap Policy (2026); Medicare & You 2027, p. 82. Plan-letter availability depends on whether you were new to Medicare before or after Jan 1, 2020.
Two more Florida rules are worth knowing before you apply. The Department of Financial Services says Florida Medigap policies are sold on an issue-age basis: your premium isn't raised because you get older, but it's set by your age when you apply. And every Florida Medigap policy has a 30-day free look under section 627.674, which lets you return it for a full refund. DFS notes the free look doesn't apply to Medicare Advantage plans.
My read: if you're past your trial period and thinking about leaving Medicare Advantage, apply for the Medigap policy first and get an answer before you send the Medicare Advantage change. Then time the two so the Medigap policy starts the same day Original Medicare does. Do it the other way round and you risk landing on Original Medicare with no supplement.
A worked 2027 timeline (hypothetical)
Here's how the dates line up for one made-up person. She turned 65 in March 2026, has lived in Sarasota for years, and joined a Medicare Advantage plan with drug coverage during her Initial Enrollment Period, when she first became eligible for Part A at 65 (her Part A started March 1). The plan started April 1, 2026. By January she's unhappy with the network and wants Original Medicare, a Medigap policy and a stand-alone drug plan.
| Date | What happens | Why |
|---|---|---|
| Dec 7, 2026 | Fall Open Enrollment closes; she does nothing | She can still use the MA Open Enrollment Period in January because she's in Medicare Advantage |
| Dec 31, 2026 | Earliest day her Florida Medigap trial-right window opens | 60 days before a March 1 disenrollment date (69O-156.0095(3)(d)) |
| Jan 1, 2027 | MA Open Enrollment Period opens | 42 CFR 422.62(a)(3) |
| Mid-January | She applies for a Medigap policy with a March 1 start | Trial right: she joined at 65 and is leaving within 12 months |
| Feb 10, 2027 | She joins a stand-alone Part D plan; the plan gets her request that day | Joining the drug plan disenrolls her from Medicare Advantage automatically |
| Mar 1, 2027 | Original Medicare, the Part D plan and the Medigap policy all start | First of the month after the request (42 CFR 422.68(c)); 11 months after her plan began |
| Mar 31, 2027 | MA Open Enrollment Period closes | Her one change is already used |
| May 3, 2027 | Last day of her trial-right Medigap window | 63 days after the March 1 disenrollment date |
Source: 42 CFR 422.62(a)(3); 42 CFR 422.68(c); 42 CFR 423.38(e); F.A.C. 69O-156.0095; Medicare & You 2027, p. 75. The person and dates are invented to show the math; dates computed.
Change one fact and the story changes. If her plan had started March 1, 2026 instead, a March 1, 2027 exit would land right at the 12-month line, and I'd want her to move a month earlier rather than argue about it. If she'd been in Medicare Advantage since 2022, the Medicare side would work exactly the same way, but the Medigap application could be underwritten and declined.
Why this window matters in Florida
Most Florida Medicare beneficiaries are now in a private plan. CMS counted 5,344,538 people on Medicare in Florida in July 2026, and 3,051,948 of them (57.1%) were in Medicare Advantage or another health plan rather than Original Medicare. In July 2019 the share was 46.2%. Most of them can use this window in 2027; cost-plan, PACE and MSA members, and some other plan types in that count, can't.
Source: CMS, Medicare Monthly Enrollment, Florida, July 2019 to July 2026
Show the numbers
| Medicare Advantage & other plans | |
|---|---|
| 2019 | 46.2% |
| 2020 | 48.5% |
| 2021 | 51.0% |
| 2022 | 52.9% |
| 2023 | 54.7% |
| 2024 | 56.2% |
| 2025 | 56.7% |
| 2026 | 57.1% |
More enrollees means more people who might want a mid-winter change, and more people who need to understand the Medigap catch before they make it.
What to do between now and March 31
- Use fall Open Enrollment if you can. It ends December 7 and has no one-change limit. The MA Open Enrollment Period is a backup, not a plan.
- Check your plan in January, not March. Fill a prescription, book a visit with your main doctors, and read your plan's Annual Notice of Change and Evidence of Coverage. Problems found in January give you the most room.
- Know your start dates. Write down when your Medicare Advantage plan began and whether you joined when first eligible at 65. That decides whether a Florida trial right applies.
- Line up drug coverage. Going back to Original Medicare? Join a stand-alone Part D plan in the same move. The plans that serve your address are on the Medicare.gov plan finder, and how Part D works is on our Medicare Part D in Florida page.
- Get unbiased help. SHINE, run by the Florida Department of Elder Affairs with local Area Agencies on Aging, offers one-on-one Medicare counseling at no charge. Call the Elder Helpline at 1-800-96-ELDER (1-800-963-5337). You can also call 1-800-MEDICARE (1-800-633-4227, TTY 1-877-486-2048). Medigap questions about Florida law can go to the Florida Insurance Consumer Helpline at 1-877-693-5236.
More on how Medicare works in Florida is on our Medicare in Florida page.
MA Open Enrollment Period questions
What is the Medicare Advantage Open Enrollment Period?
It runs January 1 to March 31 each year. If you're already in a Medicare Advantage plan, you can make one change: switch to another Medicare Advantage plan, or drop it for Original Medicare and join a stand-alone Part D drug plan. The change starts the first of the month after the plan gets your request.
Can I switch from Original Medicare to Medicare Advantage between January 1 and March 31?
No. The MA Open Enrollment Period is only for people already enrolled in a Medicare Advantage plan. Moving from Original Medicare to Medicare Advantage generally waits for fall Open Enrollment, October 15 to December 7, unless a Special Enrollment Period applies.
Can I change Part D plans during the Medicare Advantage Open Enrollment Period?
Only as part of leaving Medicare Advantage for Original Medicare. If you already have Original Medicare and a stand-alone drug plan, you can't switch drug plans in this window.
How many changes can I make during the Medicare Advantage Open Enrollment Period?
One. CMS guidance says you can usually submit another request before the first one takes effect, and the last request the plan receives counts. Once a change takes effect, the window is used up for the year.
Can I get a Medigap policy if I leave Medicare Advantage in Florida?
Without underwriting, generally only if you have a guaranteed-issue right, such as a trial right: you joined Medicare Advantage when first eligible at 65, or dropped Medigap to try Medicare Advantage for the first time, and you leave within 12 months. Otherwise an insurer may use medical underwriting. Florida has no birthday rule.
Federal Medicare rules, Florida law and your own plan and policy documents control what applies to you. Confirm your situation with 1-800-MEDICARE, SHINE, the Florida Department of Financial Services or a licensed agent, and talk to an attorney for legal questions.
Sources
- eCFR: 42 CFR 422.62, election of coverage under an MA plan
- eCFR: 42 CFR 422.68, effective dates of coverage and change of coverage
- eCFR: 42 CFR 423.38, enrollment periods for Part D
- CMS: Medicare Advantage and Part D Enrollment and Disenrollment Guidance, CY 2027 (updated Aug 25, 2026)
- CMS: Medicare & You 2027 handbook
- Medicare.gov: Joining a plan
- Medicare.gov: When does Medicare coverage start
- Medicare.gov: Part D costs and late enrollment penalty
- Medicare.gov: How Medigap works
- CMS: Choosing a Medigap Policy (2026)
- Medicare.gov: Plan finder
- Florida Administrative Code 69O-156.0095, guaranteed issue for eligible persons
- Florida Statutes s. 627.6741, Medicare supplement policies
- Florida Department of Financial Services: Medicare Supplement insurance overview
- CMS: Medicare Monthly Enrollment (Florida, July 2019 to July 2026)
- Florida SHINE program
- Florida Department of Elder Affairs: contact and Elder Helpline
This article is for general educational purposes only and is not legal, tax or insurance advice. Coverage depends on the actual policy, its terms, conditions and exclusions, and state law. Maru Insurance · WA License (WAOIC) #1365574 · FL License #G363233 · NPN 22261820.