The short answer
The Medicare Advantage Open Enrollment Period runs January 1 to March 31, and it is open only to people already in a Medicare Advantage plan. You can switch to another Medicare Advantage plan, or drop yours and return to Original Medicare. It cannot be used to join Medicare Advantage.
Plan year 2026. The dates above come from the enrollment period table on Medicare.gov, read on August 7, 2026. They are statutory dates rather than figures that change with the plan year, so no year is attached to them inside the sentence.
Say you are in Original Medicare on January 1 and you want to join a Medicare Advantage plan. This window does not exist for you. It only opens from inside a plan, and everything it allows runs outward or sideways, never in.
What is Medicare Advantage Open Enrollment?
The Medicare Advantage Open Enrollment Period is a plan change window open only to people already in a Medicare Advantage plan. It lets you switch to another Medicare Advantage plan, or drop yours and return to Original Medicare. It cannot be used to join one.
A note on the name, because two are in circulation. Medicare.gov calls the autumn window the Open Enrollment Period, and many people call that one the Annual Enrollment Period. This page uses the government's names for both, so the January window is the Medicare Advantage Open Enrollment Period throughout.
It sits inside the same rule as every other plan change. You can only join, switch or drop a Medicare Advantage plan, another Medicare health plan, or a Medicare drug plan at certain times, called enrollment periods.
When is Medicare Advantage Open Enrollment?
The Medicare Advantage Open Enrollment Period runs January 1 to March 31. A second route exists for people new to Medicare: the same changes are available within the first 3 months you have Medicare Part A and Part B, if you joined a plan during your Initial Enrollment Period.
Those two are listed together on the same line of Medicare.gov's enrollment table, which is why they are easy to read as one rule. They are better understood as one window with two ways of qualifying for it.
The January to March dates do not move with the plan year. They are the same three months every year, which makes this the second of exactly two general plan change windows on the calendar.
What changes can I make?
The Medicare Advantage Open Enrollment Period allows two changes. Switch to another Medicare Advantage plan, with or without drug coverage. Or drop your Medicare Advantage plan and return to Original Medicare, in which case you will also be able to join a separate Medicare drug plan. Nothing here moves you into Medicare Advantage.
The drug coverage detail in the second option matters more than it looks. Dropping a Medicare Advantage plan that included drug coverage would otherwise leave a gap, and the rule closes it by letting you join a separate Medicare drug plan on the way out.
This window allows a narrow set of moves, and knowing what it will not do saves a wasted call.
| What you want to do | Allowed in this window | Note |
|---|---|---|
| Switch to another Medicare Advantage plan | Yes | With or without drug coverage |
| Drop it and return to Original Medicare | Yes | You may add a drug plan |
| Join a Medicare Advantage plan from Original Medicare | No | This window is not that door |
The third row is the common disappointment. This window belongs to people already in a Medicare Advantage plan.
What is absent from the list is as important as what is on it. There is no option to join a Medicare Advantage plan from Original Medicare, and no option to change a standalone drug plan while staying in Original Medicare.
Anyone wanting either of those is looking at a different window, which is the subject of the next section.
The joining requirements do not change inside this window. You still need both Part A and Part B to be in a Medicare Advantage plan at all. You must live in the plan's service area. And you need your Medicare Number and your Part A and Part B coverage start dates, which are on your Medicare card.
How is it different from the Annual Enrollment Period?
The two differ in who may use them and which way they run. Medicare Open Enrollment, October 15 to December 7, is open to everyone and moves in both directions. The Medicare Advantage Open Enrollment Period, January 1 to March 31, is only for people already in a Medicare Advantage plan.
The autumn window is the wider one by a distance. It carries joining, dropping and switching a Medicare Advantage plan, moving between Original Medicare and Medicare Advantage in either direction, adding or dropping drug coverage, and joining, dropping or switching a Medicare drug plan for someone in Original Medicare.
The January window carries two of those and only for one group. That is the whole difference, and it explains why the autumn window is the one most people mean when they say enrollment.
Their effective dates differ too, which is covered in the last section, and the difference is not cosmetic.
Who is eligible to use it?
Eligibility is the defining feature of this window: it applies only if you are already in a Medicare Advantage plan. Call it the Second Window Only Opens From Inside, because on the enrollment table it is the only row whose entry condition is a plan you already hold.
The Second Window Only Opens From Inside is our naming for what that table shows when its rows are read side by side. Every other row on it is opened by a date, by being new to Medicare, or by an event. This one is opened by what you already have. The table is the government's; the naming is ours.
The claim is deliberately scoped to that table. Outside it, one Special Enrollment Period also turns on what you hold: being in a plan rated under 3 stars for the last 3 years. That one belongs to the star ratings article.
The alternative route in is the Initial Enrollment Period one. If you joined a Medicare Advantage plan when you first got Medicare, you have the first 3 months you hold Part A and Part B to change to another Medicare Advantage plan or go back to Original Medicare.
There is a plainer way to test it. If you are in Original Medicare on January 1, this window does not exist for you, whatever your plans are.
When does an Advantage Open Enrollment change take effect?
A change made in the Medicare Advantage Open Enrollment Period takes effect the first of the month after the plan gets your request. That is different from Medicare Open Enrollment, where every change starts on January 1 no matter when in the window it was made.
The practical consequence is that timing inside this window changes your start date. A request the plan receives in January starts in February. One received in March starts in April.
That makes it the more responsive of the two windows, and the reason is structural rather than generous: it exists to correct a plan year that has already begun.
The routes for making the change are the same three used in any window. Select Enroll for the plan at Medicare.gov/plan-compare. Contact the plan by phone, on its website, or by paper form, which the plan must receive before the period ends. Or call 1-800-MEDICARE at 1-800-633-4227, TTY 1-877-486-2048.
For Medicare Cost Plans, demonstration or pilot programs, and the Program of All-inclusive Care for the Elderly, none of this applies in the same way. Medicare.gov's instruction there is to contact those plans directly about when you can join.
What this means for you
The January window is narrow on purpose. It is open only from inside a Medicare Advantage plan, it runs January 1 to March 31, and it carries two moves: sideways to another Medicare Advantage plan, or out to Original Medicare with a separate drug plan available on the way.
It is not a second chance at the autumn window. Someone in Original Medicare who missed December 7 cannot use it, and nobody can use it to join Medicare Advantage.
The date your change starts also works differently here. The first of the month after the plan gets your request, rather than a single fixed January 1 for everyone.
For the wider autumn window, read the Medicare open enrollment dates article in this cluster. For the windows that open because something happened in your life, read the Special Enrollment Period article beside it.
FAQ
Can I use the January window to join a Medicare Advantage plan?
No, and this is the most common misunderstanding about it. Medicare.gov describes the Medicare Advantage Open Enrollment Period as applying only if you are already in a Medicare Advantage plan. The two changes it lists are switching to another Medicare Advantage plan, with or without drug coverage, and dropping your Medicare Advantage plan to return to Original Medicare.
Joining from Original Medicare is not among them. Someone in Original Medicare who wants to move into a Medicare Advantage plan is looking at Medicare Open Enrollment, October 15 to December 7, or at a Special Enrollment Period if a qualifying life event applies to them. The January window can take you out or sideways. It cannot take you in.
Can I change my standalone drug plan in January?
Not through this window on its own. The Medicare Advantage Open Enrollment Period is defined for people already in a Medicare Advantage plan, and the drug plan permission attached to it is specific.
If you drop your Medicare Advantage plan and return to Original Medicare, you will also be able to join a separate Medicare drug plan. That is a drug plan joined on the way out, not a free-standing switch.
Someone in Original Medicare who wants to join, drop or switch a Medicare drug plan is described under Medicare Open Enrollment, October 15 to December 7. A Special Enrollment Period may also apply, for example after involuntarily losing other drug coverage that was as good as Medicare drug coverage.
I just started Medicare and joined a plan I do not like. What can I do?
Medicare.gov names an opportunity for exactly this. If you joined a Medicare Advantage plan during your Initial Enrollment Period, you have the first 3 months you hold Medicare Part A and Part B to act. You can change to another Medicare Advantage plan, with or without drug coverage, or go back to Original Medicare with or without a drug plan.
It appears on the same line of the enrollment table as the January window, which is why the two are easy to confuse. They do the same job for different people: one for anyone already in a Medicare Advantage plan during the first three months of the year, one for anyone in their first three months of Medicare itself.
How many times can I use this window?
The enrollment table gives the window a start and an end date, January 1 to March 31, and states what changes it allows. It states no limit on how many times the window may be used, and this article will not supply one it did not read.
What the page does state is when a change takes effect: the first of the month after the plan gets your request. Because effective dates run from the request rather than from a fixed January 1, the timing of any change inside the window is what decides when your coverage actually moves.
Anyone unsure whether a further change is possible in a given year can call 1-800-MEDICARE at 1-800-633-4227, TTY 1-877-486-2048, which is the number Medicare.gov gives for help with enrollment changes.
Does this window apply to Medicare Cost Plans or PACE?
Not in the same way. Medicare.gov handles those separately: for details about when you can join Medicare Cost Plans, demonstration or pilot programs, or the Program of All-inclusive Care for the Elderly, it says to contact the plans that offer those options.
That is a genuinely different answer from the one given for Medicare Advantage plans and Medicare drug plans, whose windows are published nationally. It matters because those other plan types are still part of Medicare, so a reader can reasonably assume the same calendar applies to them. Medicare.gov does not make that claim, and neither does this page.
