Medicare Advantage Special Enrollment Periods: When You Can Make a Change

Most people can only join, switch, or drop a Medicare Advantage or Part D plan during the Annual Enrollment Period each fall, or the Medicare Advantage Open Enrollment Period each winter. But certain life events open a Special Enrollment Period (SEP), a window to make a plan change outside those usual dates.

There are dozens of SEP situations recognized by Medicare, each with its own timing and rules. This guide walks through the most common ones, grouped by the kind of life event that triggers them, so it’s easier to figure out whether a change in circumstances opens a window to act now rather than waiting for the next enrollment period.

What Is a Special Enrollment Period

A Special Enrollment Period is a window, defined by Medicare.gov, that opens when a specific qualifying event happens. Depending on the event, an SEP might allow joining a Medicare Advantage or Part D plan for the first time, switching to a different plan, or dropping a plan to return to Original Medicare. The length of the window and what changes are allowed both depend on which SEP applies.

Missing an SEP window generally means waiting until the next Annual Enrollment Period, which can mean months without the coverage that actually fits a person’s current situation.

SEPs Triggered by a Move

• Moving to a new address outside a plan’s service area. The window opens the month of the move (or the month before, if the plan is notified in advance) and runs for 2 full months afterward.
• Moving somewhere still in the plan’s service area, but with new plan options available. Same timing as above.
• Moving back to the U.S. after living abroad. A 2-month window opens after returning.
• Moving into, or out of, an institution such as a nursing home or rehabilitation hospital. Changes are allowed for as long as someone lives there, plus 2 full months after moving out.
• Being released from incarceration, with Part A and/or Part B coverage kept active during that time. A 2-month window opens after release.

SEPs Triggered by Losing Other Coverage

• No longer eligible for Medicaid. A 3-month window opens from whichever comes later: losing eligibility or being notified of the loss.
• Leaving employer or union coverage, including COBRA. A 2-month window opens after that coverage ends.
• Involuntarily losing other creditable prescription drug coverage (coverage considered as good as Medicare’s), or being told existing coverage no longer qualifies as creditable. A 2-month window applies.
• Leaving a Medicare Cost Plan that included drug coverage. A 2-month window opens.
• Dropping coverage in a Program of All-Inclusive Care for the Elderly (PACE) plan. A 2-month window opens.

SEPs for Dual Eligible and Extra Help Situations

People with both Medicare and Medicaid, or who receive Extra Help (the federal program that helps pay Part D drug costs), have more flexibility than most Medicare enrollees:

• Having Medicare and Medicaid, or receiving Extra Help. A change to a different drug plan, or a switch from a Medicare Advantage plan with drug coverage back to Original Medicare, is generally available once a calendar month.
• Having full Medicaid benefits. Joining or switching to a plan that coordinates Medicare and Medicaid coverage (called an integrated Dual Eligible Special Needs Plan) is generally available once a month, where one is offered in the area.
• Finding out Extra Help eligibility won’t continue into the next year. A 3-month window opens from whichever comes later: the eligibility change or the notice of it.
• Being enrolled in a State Pharmaceutical Assistance Program (SPAP). A plan change is generally available once during the calendar year, and again if SPAP eligibility is later lost.

SEPs Tied to Plan Problems

Sometimes the SEP isn’t about a personal life event at all. It’s about something happening to the plan itself:

• CMS takes an official sanction against a plan for a compliance problem. A window opens when the sanction begins and stays open until it ends or a new plan is chosen, whichever happens first.
• A state takes over a plan because of financial trouble. Similar timing to a CMS sanction.
• Medicare ends a plan’s contract outright. A window opens 1 month before the contract ends and stays open for 2 full months after.
• A plan and Medicare mutually agree to end their contract. A window opens 2 months before the end date and stays open for 1 month after.
• A plan’s contract simply isn’t renewed for the next year. This window runs from December 8 through the last day of February.

Other Situations Worth Knowing About

• The Medicare Advantage “trial period.” Someone who joins a Medicare Advantage plan the first time they’re eligible for Medicare has up to 12 months to switch back to Original Medicare, and generally keeps the right to buy a Medigap policy without medical underwriting during that window.
• The 5-star SEP. Where a 5-star-rated Medicare Advantage, Part D, or Cost plan is available locally, a one-time switch into it is allowed between December 8 and November 30 of the following year.
• A plan rated below 3 stars for 3 years running. A switch to a different plan is allowed at any point while enrolled in that low-performing plan.
• A qualifying chronic condition. Where a Chronic Care Special Needs Plan serves a specific diagnosis, joining is generally available at any time, though switching plans again afterward isn’t part of this particular SEP.
• Errors, misleading information, or plan network changes. If a federal representative, a plan, or a SHIP counselor gave inaccurate information that led to a wrong enrollment decision, or a plan’s network changes significantly, a 2-month window to fix the situation is generally available. These situations are evaluated case by case.

This list covers the most common situations, but it isn’t exhaustive. Medicare recognizes other exceptional circumstances, including natural disasters or emergencies that get in the way of enrolling during a normal window.

How to Use an SEP

• Confirm the specific SEP that applies. The event, and sometimes the exact date it happened, determines the timing and what changes are allowed.
• Act within the window. Most SEPs run 2 to 3 months, though a few (like moving into a nursing home) stay open for as long as the situation lasts.
• Know that coverage generally starts the first day of the month after a completed enrollment request, though a few SEPs (like the AEP-adjacent contract-ending situations) work differently.
• Keep documentation. A move confirmation, a coverage-loss notice, or a Medicaid eligibility letter can help resolve any question about whether a particular window applies.

SEP, AEP, or OEP: Which One Applies

An SEP is different from the two enrollment periods that apply to nearly everyone: the Annual Enrollment Period each fall and the Medicare Advantage Open Enrollment Period each winter. Senioridy’s guide to choosing and switching Medicare Advantage plans covers those two windows in detail, including what can and can’t be changed during each one. And for anyone specifically weighing a permanent move back to Original Medicare, Senioridy’s guide on switching back to Original Medicare from Medicare Advantage walks through the timing and Medigap considerations specific to that decision.

Getting Help

Confirming whether a specific situation qualifies for an SEP, and exactly how long the window lasts, is often easier with help. A State Health Insurance Assistance Program (SHIP) counselor offers this guidance for free at shiphelp.org, and 1-800-MEDICARE can also confirm SEP eligibility directly.

Whatever coverage a family lands on, having the right care providers in place matters just as much as the plan details. Search Senioridy’s in-home senior care directory to find providers in your area.

This article is for informational purposes only and does not constitute legal, financial, or medical advice. Special Enrollment Period rules, timing, and eligibility are set by CMS and are subject to change. For free, personalized Medicare guidance, contact your State Health Insurance Assistance Program (SHIP) counselor at shiphelp.org, available in every state at no cost. Always confirm current SEP eligibility directly with Medicare or 1-800-MEDICARE before making a coverage decision.