To join a Medicare Advantage plan, you must meet three basic requirements: be enrolled in both Medicare Part A and Part B, live in the plan’s service area, and be a U.S. citizen or lawfully present in the United States. Beyond those fundamentals, a few additional rules and special circumstances can affect whether you qualify.
The Three Core Requirements
Medicare Advantage (also called Medicare Part C) is an alternative way to receive your Medicare benefits through a private insurer rather than through Original Medicare. But it doesn’t replace Part A and Part B. You need both of them active before you can enroll in any Medicare Advantage plan. Part A covers hospital stays and Part B covers doctor visits, outpatient care, and preventive services. If you only have one or the other, you’re not eligible.
You also must live within the plan’s service area. Medicare Advantage plans operate in specific geographic regions, and each plan defines where it offers coverage. If you move out of that service area after enrolling, you’ll need to switch to a plan available in your new location or return to Original Medicare. For one specific plan type, the Medicare Savings Account (MSA) plan, you’re disqualified if you spend more than 183 days per year outside the United States.
The citizenship or legal presence requirement applies broadly. You must be either a U.S. citizen or be lawfully present in the country.
When You Can First Enroll
Most people become eligible for Medicare at age 65. Your Initial Enrollment Period is a seven-month window that starts three months before the month you turn 65 and ends three months after it. This is your first opportunity to sign up for Part A, Part B, and a Medicare Advantage plan. If you’re already receiving Social Security benefits, you’ll be enrolled in Parts A and B automatically, but choosing a Medicare Advantage plan is always a separate, voluntary step.
People under 65 who qualify for Medicare due to a disability or certain medical conditions follow a different timeline but face the same core eligibility requirements once they have Part A and Part B in place.
You Still Pay Your Part B Premium
A common point of confusion: enrolling in Medicare Advantage does not eliminate your Part B premium. You must continue paying it for as long as you’re enrolled. Many Medicare Advantage plans charge an additional monthly premium on top of Part B, though some plans have a $0 additional premium. Either way, the Part B cost remains yours.
End-Stage Renal Disease No Longer Blocks Enrollment
Before 2021, people with end-stage renal disease (ESRD), meaning permanent kidney failure requiring dialysis or a transplant, were generally barred from joining Medicare Advantage plans. That restriction was removed by the 21st Century Cures Act. Today, people with ESRD can choose either Original Medicare or a Medicare Advantage plan for their coverage.
What Disqualifies You
Incarceration is the most significant disqualifying factor. If you are in custody in a jail, prison, or similar institution, CMS considers that to be outside any plan’s service area. You cannot enroll while incarcerated, and if you’re already enrolled when incarceration begins, you’ll be disenrolled effective the first day of the month after your incarceration starts. This applies whether you’re behind bars, on medical furlough, required by criminal law to live in a mental health facility, or have escaped from confinement.
Living outside the United States full-time also effectively disqualifies you, since you won’t be within any plan’s service area. And as noted above, MSA plans specifically set the threshold at 183 days abroad per year.
Special Needs Plans Have Extra Criteria
Medicare Advantage includes a category called Special Needs Plans (SNPs) that serve people with specific health situations. These plans must meet all the standard eligibility requirements plus additional conditions depending on the type:
- Dual Eligible SNPs (D-SNPs) are for people who qualify for both Medicare and Medicaid. You must be enrolled in your state’s Medicaid program to join.
- Chronic Condition SNPs (C-SNPs) are for people with severe or chronic illnesses. Each plan specifies which conditions it covers, and membership can be limited to a single condition or a group of related conditions.
- Institutional SNPs (I-SNPs) are for people who live in an institution such as a nursing home or long-term care facility. You’ll need to confirm the plan has providers that serve residents where you live.
With all three SNP types, you can only stay enrolled as long as you continue to meet the plan’s special conditions. If your Medicaid eligibility ends, for instance, you’d lose eligibility for a D-SNP.
Enrollment Periods Beyond Your Initial Window
If you miss your Initial Enrollment Period or want to make changes later, there are other windows. The Annual Election Period runs from October 15 through December 7 each year, and any changes take effect January 1. During the Medicare Advantage Open Enrollment Period from January 1 through March 31, you can switch between Medicare Advantage plans or drop your plan and return to Original Medicare.
Special Enrollment Periods are available in certain life circumstances. Moving out of your plan’s service area, losing other insurance coverage, or wanting to join a plan with a 5-star quality rating can all trigger a special window to make changes outside the regular schedule.
Your Trial Right if You’re New
If you dropped a Medigap (Medicare Supplement) policy to join a Medicare Advantage plan for the first time, you get a one-time 12-month trial right. During that period, you can return to Original Medicare and get your old Medigap policy back, as long as the same insurer still sells it. If that specific policy is no longer available, you may be able to purchase certain other Medigap policies depending on your state’s rules and when you first became eligible for Medicare.
Similarly, if you joined a Medicare Advantage plan when you first became eligible for Part A at 65, you can switch to Original Medicare and buy a Medigap policy within your first year without being subject to medical underwriting. This protection exists so that trying Medicare Advantage for the first time doesn’t permanently lock you out of supplemental coverage options.