Medicare Initial Enrollment Period: When It Starts, What to Do
Medicare Initial Enrollment Period: When It Starts, What to Do
The Initial Enrollment Period is your first — and best — chance to sign up for Medicare without penalties. It's a fixed 7-month window that opens three months before your 65th birthday month, includes your birthday month, and closes three months after.
Miss it without qualifying employer coverage, and you're looking at delayed coverage and lifetime premium surcharges.
How the 7-Month Window Works
The IEP breaks down like this:
Months 1–3 (before your birthday month): The ideal enrollment window. Sign up here and Part B coverage starts on the first day of your birthday month — no gap.
Month 4 (your birthday month): Coverage starts the first of the following month.
Months 5–7 (after your birthday month): Coverage is delayed by one to three months beyond enrollment. The longer you wait within this window, the longer the gap.
The first-of-the-month rule: If your birthday falls on the 1st of any month, your IEP shifts one full month earlier. Born on June 1st? Your IEP runs from February through August, not March through September. This catches people off guard because it means your coverage can start a month earlier than expected — May 1st instead of June 1st.
What Happens During the IEP
During these seven months, you can:
- Enroll in Part A (hospital insurance) — usually premium-free if you have 40+ work credits
- Enroll in Part B (medical insurance) — $202.90/month in 2026
- Sign up for a Medicare Advantage plan (Part C) — as an alternative to Original Medicare
- Enroll in a standalone Part D plan for prescription drug coverage
- Buy a Medigap supplement — your 6-month Medigap Open Enrollment Period starts the first month Part B is active, giving you guaranteed-issue access with no medical underwriting
The IEP is the only time all these doors are open simultaneously without restrictions.
Who Can Skip the IEP Without Penalty
If you're covered by a group health plan through active employment — your job or your spouse's, at a company with 20 or more employees — you can delay Part B enrollment without penalty. When that coverage ends, you'll get an 8-month Special Enrollment Period to sign up.
Plans that do not protect you from penalties if you skip the IEP:
- COBRA continuation coverage
- Retiree health benefits
- Individual marketplace (ACA) plans
- VA health care
- TRICARE (for military retirees not on active duty)
The consequences of relying on non-qualifying coverage and skipping the IEP are severe: a permanent 10% Part B premium surcharge for each full year of delay, plus a coverage gap until the next General Enrollment Period (January–March).
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Get the Medicare Enrollment Guide: When and How to Sign Up — Quick-Start Checklist
Everything in this article as a printable checklist — plus action plans and reference guides you can start using today.
What to Do Right Now
If your 65th birthday is within the next six months:
- Check whether you're already receiving Social Security benefits — if so, Medicare Parts A and B will be enrolled automatically
- If not, apply at ssa.gov/benefits/medicare during the first three months of your IEP
- Start researching Medigap plans or Medicare Advantage in your area
- If you have employer coverage, gather your plan details to determine whether you can safely delay
The Medicare Enrollment Guide maps out the full IEP timeline alongside every other enrollment window, with specific action steps for each scenario and the forms you'll need.
Get Your Free Medicare Enrollment Guide: When and How to Sign Up — Quick-Start Checklist
Download the Medicare Enrollment Guide: When and How to Sign Up — Quick-Start Checklist — a printable guide with checklists, scripts, and action plans you can start using today.