A Medicare enrollment period is a specific window of time during which you can sign up for Medicare, make changes to your existing coverage, or switch between Medicare plans. Understanding the different enrollment periods and when they apply to you is one of the most important aspects of Medicare planning because missing an enrollment deadline can result in permanent premium penalties or gaps in coverage.
Initial Enrollment Period
The Initial Enrollment Period — IEP — is the first opportunity most people have to enroll in Medicare. It is a seven month window that surrounds your 65th birthday:
- Three months before the month you turn 65
- The month you turn 65
- Three months after the month you turn 65
During this period you can enroll in Medicare Part A, Part B, and Part D and choose between original Medicare and Medicare Advantage. Enrolling before your birthday month means your coverage begins on the first day of your birthday month. Enrolling during or after your birthday month delays the start of your coverage.
It is generally recommended to enroll as early as possible during your IEP — in the three months before you turn 65 — to ensure continuous coverage without gaps.
General Enrollment Period
The General Enrollment Period — GEP — runs from January 1 through March 31 each year. It is available to people who did not enroll in Medicare Part A or Part B during their Initial Enrollment Period and do not qualify for a Special Enrollment Period.
Coverage for people who enroll during the General Enrollment Period begins July 1 of that year. People who enroll during the GEP may also be subject to late enrollment penalties for Part B and Part D.
Annual Open Enrollment Period
The Annual Open Enrollment Period — also called the Fall Open Enrollment Period — runs from October 15 through December 7 each year. During this period anyone with Medicare can:
- Switch from original Medicare to a Medicare Advantage plan
- Switch from a Medicare Advantage plan back to original Medicare
- Switch from one Medicare Advantage plan to another
- Join, switch, or drop a Medicare Part D prescription drug plan
Changes made during the Annual Open Enrollment Period take effect January 1 of the following year. This is the most important enrollment period for people who already have Medicare and want to review or change their coverage.
Medicare Advantage Open Enrollment Period
The Medicare Advantage Open Enrollment Period runs from January 1 through March 31 each year. During this period people who are already enrolled in a Medicare Advantage plan can:
- Switch to a different Medicare Advantage plan
- Switch from Medicare Advantage back to original Medicare and join a Part D plan
This period is only available to people who are already enrolled in a Medicare Advantage plan. People with original Medicare cannot use this period to switch to Medicare Advantage — they must wait for the Annual Open Enrollment Period in the fall.
Special Enrollment Periods
Special Enrollment Periods — SEPs — are available outside of regular enrollment windows when certain qualifying events occur. Common qualifying events that trigger a Special Enrollment Period include:
- Losing employer-sponsored health insurance or other creditable coverage
- Moving out of your Medicare Advantage plan’s service area
- Your Medicare Advantage plan leaving the Medicare program
- Qualifying for or losing Medicaid
- Moving into or out of a skilled nursing facility or other institution
- Returning to the United States after living abroad
The length of the Special Enrollment Period and what changes you can make depend on the specific qualifying event. It is important to act promptly when a qualifying event occurs because most Special Enrollment Periods last only a limited time — typically two to three months.
Employer coverage and Medicare enrollment
Many people continue working past age 65 and have employer-sponsored health insurance. If you are covered by employer insurance through your own current employment or your spouse’s current employment you may be able to delay enrolling in Medicare Part B without penalty.
When you eventually leave that employer coverage you qualify for a Special Enrollment Period that allows you to enroll in Medicare Part B without a late enrollment penalty. This SEP lasts for eight months after your employer coverage ends.
It is important to note that COBRA coverage and retiree health insurance do not qualify as employer coverage for this purpose — if you rely on COBRA or retiree insurance after leaving work and delay Part B enrollment you may face a late enrollment penalty.
Late enrollment penalties
Missing enrollment deadlines without qualifying for a Special Enrollment Period can result in permanent premium penalties:
- Part B late enrollment penalty — 10 percent added to the standard Part B premium for each full 12 month period you were eligible but did not enroll. This penalty is permanent and added to your premium for as long as you have Part B.
- Part D late enrollment penalty — 1 percent of the national base beneficiary premium multiplied by the number of months you went without creditable drug coverage. This penalty is also permanent.
There is generally no late enrollment penalty for Part A because most people receive Part A premium-free based on their work history.
Medigap and enrollment timing
Medigap — Medicare Supplement Insurance — has its own enrollment rules. The best time to enroll in a Medigap policy is during your Medigap Open Enrollment Period which begins when you turn 65 and are enrolled in Medicare Part B and lasts for six months. During this period you have a guaranteed right to buy any Medigap policy sold in your state regardless of your health status.
Outside of this window insurers can use medical underwriting to charge higher premiums or deny coverage in most states. This makes enrolling in a Medigap policy during the open enrollment window especially important.
Getting help with Medicare enrollment
The enrollment process can be confusing especially when coordinating Medicare with employer coverage or other insurance. Free help is available through:
- State Health Insurance Assistance Program — SHIP — provides free unbiased counseling to Medicare beneficiaries and their families. Find your state’s SHIP at shiphelp.org or call 1-800-MEDICARE.
- Social Security Administration — handles Medicare enrollment for most people. Apply at ssa.gov or call 1-800-772-1213.
- Medicare — visit medicare.gov or call 1-800-MEDICARE for information about enrollment periods and options.
Key terms to know
- Initial Enrollment Period — IEP — the seven month window around your 65th birthday when you first become eligible for Medicare
- General Enrollment Period — GEP — January 1 through March 31, available to people who missed their IEP
- Annual Open Enrollment Period — October 15 through December 7, when Medicare beneficiaries can change their coverage
- Medicare Advantage Open Enrollment Period — January 1 through March 31, for people already enrolled in Medicare Advantage
- Special Enrollment Period — SEP — a time-limited enrollment opportunity triggered by a qualifying life event
- Late enrollment penalty — a permanent premium increase for failing to enroll in Part B or Part D when first eligible
- Creditable coverage — prescription drug coverage at least as good as Medicare Part D that exempts a person from the Part D late enrollment penalty
Sources
- Medicare.gov — Enrollment Periods
- Centers for Medicare and Medicaid Services
- Social Security Administration — ssa.gov
- State Health Insurance Assistance Program — shiphelp.org
This article is for general informational purposes only and does not constitute legal or financial advice. Medicare enrollment rules are subject to change. Visit medicare.gov or contact your state SHIP program for the most current information specific to your situation.