A Medicare Advantage plan that stops operating for 2027 does not leave its members without a next step. Medicare.gov’s special enrollment rules set a window for switching to a new plan or falling back to Original Medicare, running from December 8 through the last day of February. A member who lets that window close is enrolled in Original Medicare automatically, whether or not it covers what the old plan did.
What the switch window doesn’t compare: December 8 through the end of February lets a member switch plans, but it doesn’t set the finalists side by side on cost, drugs and doctors the way The 2027 Medicare Open Enrollment Decision Kit does. Compare the switch options on cost, drugs and doctors →
The December 8 Switch Window
Medicare’s Special Enrollment Periods page lays out three separate ways a Medicare Advantage or Part D plan can leave a member needing a new one, and each carries its own calendar. When a plan’s contract with Medicare simply is not renewed for the coming year, the enrollment window runs from December 8 through the last day of February of the following year, and a member can use it to join a different Medicare Advantage plan or move back to Original Medicare. That is different from what happens if Medicare itself ends a plan’s contract, which opens a window from one month before the contract ends to two months after, and different again from a plan that exits the program voluntarily mid-year, which opens a window running from two months before the exit to one month after it. The December 8 window applies specifically to the case here: a plan still operating today that will not be back for the next calendar year.
Defaulting Into Original Medicare
A member who takes no action before the window closes does not stay in limbo: Medicare enrolls them in Original Medicare once the old plan’s coverage ends. Original Medicare pays hospital and outpatient claims but carries no drug benefit of its own, so prescription coverage after the switch has to come from a stand-alone Part D plan added separately, and the costs Original Medicare leaves uncovered can be significant enough that a Medicare Supplement, or Medigap, policy becomes worth pricing out at the same time. Anyone who skips that step and simply lets the default happen ends up with hospital and doctor coverage attached to no drug plan at all, a gap that can sit open for months before it is noticed at the pharmacy counter.
Two Enrollment Windows, Back to Back
The switch window for a non-renewing plan starts the day after Medicare’s general fall enrollment period ends. That earlier window runs from October 15 through December 7 every year, open to any Medicare Advantage or Part D enrollee who wants to join, drop or switch plans, or add or drop drug coverage, for changes that take effect January 1, not only to someone whose plan is leaving. Medicare’s guidance on that period notes that a member moving into Original Medicare may need to separately enroll in a drug plan and could consider a Medigap policy for the costs Original Medicare does not pick up. Because the two windows sit back to back, a member whose plan is not renewing effectively gets almost three extra months beyond the general deadline that everyone else works against.
A Notice That Doesn’t Arrive the Same Way for Everyone
Plans that intend to keep operating mail their own notice every September, an Annual Notice of Change describing what is different about cost and coverage starting in January. A plan that is not returning follows a later timetable and serves a different purpose: its notice functions as the trigger for the December 8 window itself, not a summary of what changed inside a plan that is staying put. Medicare’s guidance on the Annual Notice of Change tells members who do not receive one on schedule to contact the plan directly, a reminder of how much of this process depends on a piece of mail actually showing up.
Weighing a Medigap Policy on the Way Out
A member moving from Medicare Advantage back into Original Medicare during the switch window can also look at buying a Medigap policy to help with costs Original Medicare does not cover. Medicare’s guide to buying a Medigap policy explains that most people get a six-month window right after Part B starts to buy one without medical underwriting, and outside that period, without a specific guaranteed-issue right tied to something like a plan leaving the market, an insurer is not required to sell a policy at all. Medicare.gov’s enrollment materials are clear that the December 8-to-February switch right covers changing Medicare Advantage or Part D plans and returning to Original Medicare, not a separate guaranteed right to buy a Medigap policy on those same terms.
Standardized Letters, Not a Single Product
Medigap policies sold during any enrollment window are standardized and identified by a letter, such as Plan G or Plan K, so the same letter covers the same benefits no matter which company sells it, though premiums for that letter can still vary by insurer and by state. A member who already owns a Medigap policy and wants to change it later faces a narrower path: Medicare’s page on changing a Medigap policy says that outside a six-month open enrollment window or a guaranteed-issue right, a switch generally is not protected, and an insurer can require medical underwriting or make a new applicant wait out a pre-existing condition period if the current policy has been held for less than six months. None of that applies to the specific right at issue here, since the December 8 window is about replacing a Medicare Advantage or Part D plan, not about trading one Medigap letter for another.
The Non-Renewal Switch, Without a Side-by-Side
A member who lets the December-to-February window lapse is enrolled automatically in Original Medicare, with no drug coverage attached and no comparison ever run against what a replacement Medicare Advantage plan would have covered. The window sets a hard clock for switching, but it never sorts the available plans by premium, drug formulary or in-network doctors on its own.
The 2027 Medicare Open Enrollment Decision Kit pairs a cost calculator spreadsheet with a provider call script, so the same window that ends in February can also produce a plan-by-plan comparison before the default takes effect.
Compare the finalists side by side in The 2027 Medicare Open Enrollment Decision Kit.
This article was produced with AI assistance and reviewed by a human editor before publication.
