The 4 Medicare Enrollment Windows
Each enrollment period has specific dates and rules. Understanding which one applies to you is the first step to avoiding costly mistakes.
Initial Enrollment Period (IEP)
Starts 3 months before your birth month, includes your birth month, and ends 3 months after. This is the most important window — missing it can mean late enrollment penalties for life.
Annual Enrollment Period (AEP)
Switch Medicare Advantage plans, return to Original Medicare, join or change a Part D drug plan. Changes take effect January 1st of the following year.
Open Enrollment Period (OEP)
If you're already enrolled in Medicare Advantage, you can switch to a different MA plan or return to Original Medicare + Part D during this period.
Special Enrollment Period (SEP)
Triggered by qualifying life events — losing employer coverage, moving, gaining Medicaid, and more. Allows enrollment outside normal windows without penalties.
⚠️ Late Enrollment Penalties
If you don't sign up for Part B when first eligible and don't have qualifying employer coverage, you may pay a 10% premium penalty for each 12-month period you could have had Part B but didn't. This penalty lasts for the rest of your Medicare coverage.
How to Enroll in Medicare
- Online: Visit SSA.gov to apply for Medicare Parts A & B
- By Phone: Call Social Security at 1-800-772-1213 (TTY: 1-800-325-0778)
- In Person: Visit your local Social Security office
- With Us: We'll guide you through the process and help you choose the best plan — completely free
Delayed Enrollment — Working Past 65
If you're still working at 65 with employer-sponsored health insurance, you may be able to delay Medicare Part B without penalty. When you retire (or lose employer coverage), you'll have a Special Enrollment Period to sign up.
You may need to submit these forms to Medicare:
After Enrollment — Choosing Your Path
Once enrolled in Medicare Parts A & B, you have two main options:
- Original Medicare + Medigap + Part D — Maximum flexibility. See any Medicare-accepting provider. Add a Supplement to cover out-of-pocket costs and a Part D plan for prescriptions.
- Medicare Advantage (Part C) — All-in-one coverage through a private insurer. Often includes drugs, dental, vision, and hearing. Network-based with lower premiums but less provider flexibility.
Not sure which path is right for you? That's exactly what we help with — call us for a free consultation.
Frequently Asked Questions
You'll need to wait for the General Enrollment Period (Jan 1 – Mar 31), with coverage starting July 1st. You may also face a permanent late enrollment penalty on your Part B premium.
Yes. During the Annual Enrollment Period (Oct 15 – Dec 7) you can switch plans. If you have Medicare Advantage, you can also make one change during the Open Enrollment Period (Jan 1 – Mar 31).
Part A is free for most people, so there's usually no downside. However, if you're contributing to an HSA, enrolling in Part A will disqualify you from further HSA contributions.
Your employer's HR or benefits department can tell you. Creditable coverage must be at least as good as Medicare's standard coverage. If it's not creditable, you may face penalties for late enrollment.