A Special Enrollment Period lets you enroll in Medicare or change certain coverage outside the usual enrollment windows after a qualifying event, such as losing job-based insurance or moving.
Medicare has several Special Enrollment Periods, or SEPs. They allow enrollment or plan changes outside standard windows after certain events. What you can do and how long you have depend on the event and the type of coverage you want.
Special Enrollment for Part A and Part B
A common Part B SEP applies if you have or had coverage through your or your spouse’s current employment. For certain people with disability-based Medicare, coverage through another family member’s current employment can also qualify. The usual employment SEP does not apply to Medicare eligibility based on End-Stage Renal Disease (ESRD), or permanent kidney failure; ask Social Security about that separate route.
You can generally enroll while that coverage continues or during the eight months after the employment or coverage ends, whichever comes first. COBRA does not extend this eight-month period.
Other Part A and Part B SEPs may apply after loss of Medicaid, certain errors by an employer or health plan, release from incarceration, or other exceptional circumstances.
Special Enrollment for Medicare Advantage and Part D
You may receive an SEP to change health or drug plans when you:
- Move outside a plan's service area
- Lose employer, union, or other creditable coverage
- Gain or lose Medicaid or Extra Help
- Enter, live in, or leave an institution
- Enroll in certain qualifying programs
- Are affected by a plan contract problem or government-declared emergency
Each event has its own dates and rules for which changes you can make. Medicare lists them in its official Special Enrollment Period guidance.
Different Events, Different Clocks
- Part B after current employment or its group coverage ends: generally eight months from whichever ends first. It does not provide insurance during the wait.
- Advantage or Part D after involuntary loss of creditable drug coverage: generally through two full months after the month you lose coverage or are told it is no longer creditable, whichever is later.
- A move outside a plan’s service area: generally through two full months after the move; telling the plan in advance can open the window the month before the move. A move within the area can also qualify when new plan options become available.
Use the event-specific Medicare rules rather than applying one of these deadlines to loss of Medicaid or another event.
What Does Not Automatically Create an SEP?
Simply disliking a plan, receiving a high bill, or discovering that a doctor is out-of-network does not always create an SEP. However, inaccurate plan information, significant network changes, or other exceptional circumstances may qualify in limited cases.
Do not cancel existing coverage until you know whether an SEP applies and when replacement coverage will start.
What Documents Should You Keep?
Save:
- Employer coverage termination notices
- COBRA notices
- Proof of a move
- Medicaid or Extra Help notices
- Plan letters
- Dates and reference numbers from calls
- Evidence of inaccurate information, if relevant
How to Request an SEP
For Part A and Part B, contact Social Security with your coverage and employment dates. For Medicare Advantage or Part D, contact Medicare or the plan you want to join. Explain what happened and ask what changes you can make, what documents you need, and when you must act. Save confirmation of when the new coverage will start.
Medicare policy sources last checked: October 8, 2026.