You can disenroll from a Medicare Advantage plan during three windows: the Annual Enrollment Period from October 15 through December 7, the Medicare Advantage Open Enrollment Period from January 1 through March 31, or a Special Enrollment Period triggered by a qualifying life event. Outside those windows, you’re locked in until the next one opens. The date matters more than most people expect, because two separate 63-day clocks start ticking the moment your Medicare Advantage coverage ends: one for prescription drug coverage, one for a Medigap policy.
Annual Enrollment Period: October 15 to December 7
This is the broadest window. Between October 15 and December 7 each year, you can drop your Medicare Advantage plan and return to Original Medicare, switch to a different Medicare Advantage plan, or enroll in a standalone Part D prescription drug plan. Any change you make takes effect January 1 of the following year.1Medicare. Open Enrollment
Medicare Advantage Open Enrollment Period: January 1 to March 31
If you’re enrolled in a Medicare Advantage plan on January 1, you get a second chance to make a change between January 1 and March 31. You can switch to a different Medicare Advantage plan, or drop your plan entirely and go back to Original Medicare. If you return to Original Medicare during this window, you can also join a standalone Part D plan. You’re limited to one change during this period.2Medicare. Understanding Medicare Advantage and Medicare Drug Plan Enrollment Periods
This window is only for people who already have Medicare Advantage on January 1. If you’re on Original Medicare, it doesn’t apply to you.
Special Enrollment Periods
Certain life events open a window outside the standard enrollment periods. You qualify for a Special Enrollment Period if you:
- Move out of your plan’s service area
- Move back to the U.S. from another country
- Are released from incarceration
- Gain or lose Medicaid or Extra Help eligibility
- Move into or out of an institution like a nursing home
The length of the window varies by event, but most give you two full months after the qualifying event to make a change.3Medicare. Special Enrollment Periods
There’s also a separate option worth knowing about: if a Medicare Advantage or Part D plan with a 5-star quality rating is available where you live, you can use a one-time Special Enrollment Period between December 8 and November 30 of the following year to switch into that plan.4Medicare. Special Enrollment Periods
How Disenrollment Actually Happens
The simplest path is often indirect. If you enroll in a new Medicare Advantage plan or a standalone Part D plan during an eligible enrollment period, your old plan cancels automatically once the new coverage kicks in. You don’t need to notify your previous plan separately.5Medicare. What if I Want to Switch, Drop, or Rejoin Drug Coverage?
To leave without switching to another plan, contact your current Medicare Advantage plan directly. The plan will provide a disenrollment form or walk you through its process. Once your request is processed, you’ll receive a notice confirming the effective date. You can also call 1-800-MEDICARE (1-800-633-4227) at any point; agents are available 24 hours a day, seven days a week.6Medicare. Talk to Someone – Contact Medicare
Whichever method you use, confirm the exact date your Medicare Advantage coverage ends in writing. That date starts the two deadlines below.
What You Lose the Day Coverage Ends
Once your Medicare Advantage plan ends, you’re covered by Original Medicare (Part A and Part B). You also lose any extras your plan bundled in, which typically means prescription drug coverage and often dental, vision, hearing, and fitness benefits. Original Medicare doesn’t cover those things.
There’s one other structural change worth understanding before you disenroll. Medicare Advantage plans are required to cap your annual out-of-pocket spending for in-network services. Original Medicare has no such cap. A serious illness or long hospital stay under Original Medicare without supplemental coverage has no ceiling on what you could owe. That’s why the Medigap deadline below matters as much as it does.
The 63-Day Deadline for Part D Drug Coverage
Most Medicare Advantage plans include prescription drug coverage. When your plan ends, that coverage ends with it, and Original Medicare on its own has no drug benefit. If you want prescriptions covered, you have to actively enroll in a standalone Part D plan.
If you go 63 or more consecutive days without Part D coverage or other creditable drug coverage (coverage at least as good as a standard Part D plan), you’ll owe a late enrollment penalty when you eventually do sign up. The penalty is 1% of the national base beneficiary premium for every month you went without creditable coverage, and it’s added to your Part D premium permanently.7Medicare. Avoid Late Enrollment Penalties It recalculates upward each year as the base premium rises. Signing up for a Part D plan during the same enrollment period you use to disenroll is the way to avoid it.
The 63-Day Deadline for Medigap
A Medigap (Medicare Supplement Insurance) policy pays some or all of the deductibles, coinsurance, and copayments Original Medicare leaves to you. Medigap works only with Original Medicare. You can’t use one while enrolled in a Medicare Advantage plan.8Medicare. Learn How Medigap Works
Whether you can buy a Medigap policy at all after leaving Medicare Advantage, and at what price, depends almost entirely on timing. Outside of specific protected windows, Medigap insurers in most states can reject your application, charge higher premiums, or impose waiting periods for pre-existing conditions.9Centers for Medicare & Medicaid Services. Choosing a Medigap Policy
Two federal guaranteed issue rights apply specifically to people leaving Medicare Advantage:
- Trial right. If you dropped a Medigap policy to join a Medicare Advantage plan for the first time, you have 12 months to return to that same Medigap policy (if the insurer still sells it) after you go back to Original Medicare.8Medicare. Learn How Medigap Works
- First-year exit. If you joined a Medicare Advantage plan when you first became eligible for Part A at 65, and you switch back to Original Medicare within the first 12 months, you can buy certain Medigap policies with guaranteed issue protection.8Medicare. Learn How Medigap Works
In either case, you must apply for the Medigap policy no later than 63 days after your Medicare Advantage coverage ends. You can also apply up to 60 days before the coverage end date. Miss the 63-day window and the guaranteed issue protection is gone.10Medicare. When Can I Buy a Medigap Policy?
If neither trial right nor first-year exit applies to you, and your initial six-month Medigap Open Enrollment Period at age 65 is already spent, then in most states you’re subject to medical underwriting when you apply. Insurers can ask health questions, deny you, price the policy based on your health, or impose a pre-existing condition waiting period of up to six months.9Centers for Medicare & Medicaid Services. Choosing a Medigap Policy A handful of states add their own protections, including annual “birthday rule” windows, but most follow only federal rules.
If you’ve been on Medicare Advantage for several years and have developed health conditions since you first enrolled, this is the biggest financial risk of disenrolling. Contact your State Health Insurance Assistance Program (SHIP) for free counseling on the Medigap rules in your state before your Medicare Advantage coverage ends, not after.
Lining Up the Timing
The sequence that keeps you protected: pick your disenrollment window, confirm the effective end date of your Medicare Advantage coverage, enroll in a Part D plan during the same window so drug coverage starts the day Original Medicare kicks in, and apply for a Medigap policy inside the 63-day window (ideally in the 60 days before the end date, so the policy is ready to start on day one). Any of those three pieces slipping out of alignment can cost you money for years, and in the Medigap case, potentially for as long as you’re on Medicare.