Key Takeaways

• In 2025, you can still sign up for Medicare if you missed your Initial Enrollment Period, but delays often mean lifetime penalties and waiting periods.

• Understanding your eligibility and timing for the General Enrollment Period and Special Enrollment Periods is critical to avoid unnecessary costs.

Missed the First Window? Here’s What Happens Next

If you turned 65 but didn’t enroll in Medicare during your Initial Enrollment Period (IEP), you’re not alone. But you should know that missing this first deadline means you may now have to wait until the General Enrollment Period (GEP) to sign up—and that can come with permanent late enrollment penalties and a delay in coverage.

Your IEP is a seven-month window: it starts three months before the month you turn 65, includes your birth month, and ends three months after. If that time has passed and you didn’t have other creditable coverage (such as from an employer), then the GEP is your next chance.

What the General Enrollment Period Offers in 2025

The General Enrollment Period happens every year from January 1 to March 31. If you enroll during this window, your Medicare coverage starts July 1 of the same year. This is your fallback option if you missed enrolling during your IEP and don’t qualify for a Special Enrollment Period.

During the GEP, you can enroll in:

• Medicare Part A (Hospital Insurance)

• Medicare Part B (Medical Insurance)

Once enrolled in Parts A and B, you can also choose to enroll in:

• A Medigap policy (subject to medical underwriting in most states)

• A Medicare Part D plan for prescription drug coverage

• A Medicare Advantage plan (if eligible)

The Cost of Enrolling Late

Late enrollment penalties are one of the most expensive consequences of missing your IEP. These penalties are not a one-time fee—they are added to your monthly premiums and can last for as long as you have Medicare.

Medicare Part B Penalty

If you delay enrollment in Part B without other creditable coverage, your premium goes up 10% for every full 12-month period you could have had Part B but didn’t. For example, a two-year delay results in a 20% higher premium every month, for life.

Medicare Part D Penalty

If you don’t sign up for Medicare drug coverage (Part D) when first eligible and go without creditable drug coverage for 63 days or more, you’ll face a permanent penalty. This penalty is calculated as 1% of the national base beneficiary premium multiplied by the number of months you were without coverage.

Exceptions That May Protect You

If you delayed Medicare enrollment because you had coverage through a current employer (yours or your spouse’s), you might qualify for a Special Enrollment Period (SEP). This period allows you to sign up for Medicare without penalty.

Special Enrollment Period Basics

• When it happens: You have 8 months to enroll in Medicare after the month your employer or union coverage ends or your employment ends—whichever comes first.

• What you can sign up for: Medicare Part A and/or Part B, and subsequently enroll in Part D or a Medicare Advantage plan.

Remember: COBRA, retiree health plans, and Veterans Affairs (VA) benefits are not considered creditable coverage for delaying Medicare Part B without penalty.

Coverage Delays to Watch Out For

When you enroll during the GEP, your Medicare coverage does not begin right away. In 2025, if you enroll between January 1 and March 31, your coverage will start on July 1.

This delay could leave you without health insurance for several months unless you have another source of coverage in place. That’s why it’s always recommended to enroll during your IEP if possible.

Strategic Enrollment After the GEP

Once you’re enrolled in Original Medicare (Parts A and B) through the GEP, you can take further steps to enhance your coverage. Here are your options after July 1:

Medicare Part D (Prescription Drug Plan)

You can enroll in a Part D plan within two months of your Medicare coverage starting. Missing this window can trigger a permanent late enrollment penalty and may limit your coverage options until the next Annual Enrollment Period (October 15 – December 7).

Medicare Advantage Plan (Part C)

You may also be able to enroll in a Medicare Advantage plan in a Special Enrollment Period triggered by gaining Medicare eligibility. Availability varies, and you should check whether you’re eligible to switch from Original Medicare to a Medicare Advantage plan after enrolling via GEP.

Medigap (Supplemental Insurance)

You have a 6-month Medigap Open Enrollment Period starting the month you’re 65 or older and enrolled in Part B. If you miss this, insurers can charge higher premiums or deny coverage due to pre-existing conditions in most states.

Understanding the Role of Creditable Coverage

Creditable coverage plays a key role in avoiding penalties. If you had coverage that is considered “creditable” (equal or better than Medicare’s coverage), you won’t be penalized for enrolling late. Here’s how it applies:

• For Part B: Employer coverage from active employment (not retiree or COBRA) counts.

• For Part D: Employer or union drug coverage, TRICARE, or VA drug benefits can be creditable.

It’s essential to keep documentation of this coverage. You may be required to prove it when applying for Medicare.

Watch for Enrollment Period Overlaps

It can be confusing, but GEP and other enrollment periods like the Medicare Advantage Open Enrollment Period (MA OEP) and the Annual Enrollment Period (AEP) don’t overlap in function.

• MA OEP (Jan 1 – Mar 31): Only for people already enrolled in Medicare Advantage who want to switch to another MA plan or go back to Original Medicare.

• AEP (Oct 15 – Dec 7): Lets you change Medicare Advantage or Part D plans. Changes take effect January 1 of the following year.

GEP is for new enrollment into Original Medicare and is not used to switch plans.

What You Can Do Now

If you know you missed your IEP and don’t qualify for a Special Enrollment Period, here are your action steps in 2025:

• Mark the GEP window: January 1 to March 31

• Prepare for coverage to start on July 1

• Anticipate possible late enrollment penalties

• Plan to enroll in a Part D or Medigap/Medicare Advantage plan shortly after your coverage begins

• Keep records of any creditable coverage you had previously

Planning Ahead Prevents Future Surprises

Medicare is not automatic unless you’re already receiving Social Security benefits. Proactive planning is essential to avoid lapses in coverage, penalties, or restrictions in plan selection.

Use your time now to:

• Evaluate your healthcare needs

• Understand what Parts A, B, D, and Medigap or Advantage plans cover

• Review potential out-of-pocket costs

• Set calendar reminders for enrollment windows

These steps can help you make better decisions when your enrollment window opens or if you’re already in your GEP period.

Don’t Let Delays Define Your Medicare Journey

If you’re enrolling through the General Enrollment Period in 2025, you’re taking the right step to secure coverage. But the consequences of enrolling late—including penalties and gaps in coverage—are real and long-term. The more you understand the timelines, rules, and options, the more control you’ll have over your healthcare future.

To make the most informed choice, consider speaking with a licensed agent listed on this website. They can walk you through your options and help ensure you’re enrolled in the right coverage at the right time.