Key Takeaways

• You have a 7-month Initial Enrollment Period (IEP) around your 65th birthday that determines your access to Medicare benefits.

• Missing your IEP can lead to lifelong late penalties, delayed coverage, and fewer choices for supplemental coverage.

Understanding the 7-Month Enrollment Window

When you turn 65, you become eligible for Medicare. But eligibility alone isn’t enough—you must act during a critical 7-month window called the Initial Enrollment Period (IEP). This window spans:

• 3 months before your 65th birthday month

• Your birthday month

• 3 months after your birthday month

This is the most important Medicare deadline you will face. Your decisions during this time directly influence your health coverage, costs, and peace of mind for years to come.

Why Your IEP Matters So Much in 2025

In 2025, Medicare continues to enforce penalties and enrollment delays for individuals who miss their IEP. If you don’t enroll in Part B or Part D when first eligible, you may pay higher premiums permanently.

Here’s why your IEP matters:

• Avoid Late Enrollment Penalties

  • Part B penalty: 10% added to your premium for every 12-month period you were eligible but didn’t enroll.

  • Part D penalty: 1% of the national base premium multiplied by the number of months you went without credible drug coverage.

• Ensure Immediate Coverage Start

  • If you enroll before your birthday month, your coverage begins the month you turn 65.

  • If you enroll during or after your birthday month, your coverage may be delayed by up to three months.

• Secure Access to Medigap or Supplemental Coverage

  • The best time to buy a Medigap policy is during your 6-month Medigap Open Enrollment Period, which starts the month you’re both 65 and enrolled in Part B. During this time, insurers can’t deny you coverage or charge you more due to pre-existing conditions.

Who Needs to Enroll During IEP

You need to enroll in Medicare during your IEP if:

• You’re turning 65 and not covered by an employer group health plan from your (or your spouse’s) current employment.

• You plan to retire at or around age 65 and won’t have employer-sponsored coverage.

• You live abroad but plan to return to the U.S. and use Medicare benefits.

You may not need to enroll yet if:

• You have active employer coverage from current work (not retiree benefits).

• Your employer has 20 or more employees and offers creditable coverage.

However, even if you delay Part B or Part D because of employer coverage, you will need to enroll promptly once that coverage ends to avoid penalties. That’s where a Special Enrollment Period (SEP) would apply.

What Happens If You Miss Your IEP

Missing your Initial Enrollment Period has serious consequences that extend beyond just paperwork delays:

• Higher Monthly Premiums for life (especially Part B and Part D)

• Delayed Coverage Start that can leave you temporarily uninsured

• Limited Medigap Access—after the Medigap Open Enrollment window closes, insurers can deny you coverage or charge more based on your health

If you miss your IEP and don’t qualify for a Special Enrollment Period, you must wait for the General Enrollment Period (GEP), which occurs from January 1 to March 31 each year. But coverage doesn’t begin until July 1—leaving a dangerous gap if you need medical care in the meantime.

Breaking Down the Parts: What You Need to Enroll In

During your IEP, you should consider enrolling in the following parts of Medicare:

Medicare Part A

• Hospital Insurance

• Most people qualify for premium-free Part A if they’ve worked 40 quarters (10 years)

• Even if you delay other parts, it’s often advisable to enroll in Part A if it’s free

Medicare Part B

• Medical Insurance

• Covers doctor visits, preventive services, durable medical equipment, and more

• Monthly premium applies ($185 in 2025; income-based adjustments may apply)

• Late enrollment results in a 10% premium penalty per 12-month delay

Medicare Part D

• Prescription Drug Coverage

• Voluntary but highly recommended unless you have other credible drug coverage

• 1% penalty per month applies if you delay enrollment without creditable coverage

Medigap (Medicare Supplement Insurance)

• Helps cover out-of-pocket costs not covered by Original Medicare (Parts A & B)

• Enroll during your 6-month Medigap Open Enrollment Period to avoid health underwriting

If You’re Still Working at 65

Many people turning 65 in 2025 are still working or covered under a spouse’s plan. In this case, your IEP still applies—but your decision might look different:

• If your employer has 20 or more employees and you’re actively working, you can delay Part B and Part D without penalty. Be sure your plan is deemed creditable.

• If your employer has fewer than 20 employees, you usually need to enroll in Medicare at 65. Medicare becomes your primary payer, and delaying enrollment could leave you underinsured.

Once your employer coverage ends, you’ll be eligible for a Special Enrollment Period to sign up for Medicare within 8 months without penalty—but only 2 months to enroll in Part D or a Medicare Advantage Plan.

When Coverage Starts Based on When You Enroll

The timing of your enrollment determines when your Medicare benefits begin:

Note: If your birthday falls on the 1st of the month, your IEP shifts back one month, and your Medicare coverage begins the month before your actual birthday.

Your Medigap Timing is Tied to Part B

Your Medigap Open Enrollment Period is not the same as your IEP. It begins when you are both 65 or older and enrolled in Part B, and it lasts for 6 months.

During this time:

• Insurers cannot deny coverage based on pre-existing conditions

• You have access to all Medigap plans available in your state

• After this period, insurers can use medical underwriting or deny coverage entirely

Avoiding Common IEP Mistakes in 2025

To protect your Medicare future, steer clear of the most frequent mistakes people make during their IEP:

• Assuming automatic enrollment—You’re automatically enrolled only if you’re already receiving Social Security or Railroad Retirement benefits.

• Waiting too long to compare options—Delays can lead to missed deadlines and higher costs.

• Forgetting about drug coverage—Part D penalties accumulate quickly and silently.

• Not understanding employer coverage rules—You must verify whether your group coverage is creditable.

What You Can Do Right Now

If you’re turning 65 soon, here are the actions you can take today:

• Mark your calendar for the 7-month IEP around your 65th birthday

• Evaluate your current health coverage and whether it’s creditable

• Research Medicare Parts A, B, and D to understand what you’ll need

• Compare Medigap and other supplemental options during your enrollment window

• Contact a licensed agent listed on this website to ask specific questions and review your options

Your Enrollment Window Shapes Everything That Comes After

Your choices during your Initial Enrollment Period in 2025 shape the future of your Medicare experience—both in terms of coverage and cost. It’s a one-time opportunity to lay a solid foundation.

Don’t assume you have more time. Don’t let employer coverage assumptions get in the way. And don’t wait for a penalty letter to realize a deadline passed.

If you want help making informed decisions, get in touch with a licensed agent listed on this website today.