How to Enroll in Medicare or Switch Your Plan

Once you have an idea of which plan is right for you, the next thing on your mind is probably when and how you can enroll or make the switch to another plan. Excellus BlueCross BlueShield can help you there, too. Ready to enroll today? Let’s get started.

When Can You Enroll in a Medicare Plan?

If you’re age 65 or older, under 65 with certain disabilities, or any age with End-Stage Renal Disease (ESRD) (permanent kidney failure requiring dialysis or a kidney transplant), you’re eligible to enroll in Medicare. There are several opportunities to enroll.

Initial Enrollment Period (IEP)

If you’re turning 65 and about to enroll in Medicare for the first time, you have a seven-month window to enroll. This window starts three months before you turn 65 and runs through the three months following the month of your 65th birthday.

  • Your enrollment will take effect on the first day of your birthday month. If you enroll after you turn 65, it will take effect on the first day of the month following your enrollment submission request.
  • If you will receive Medicare before age 65 due to a disability, you can join three months before or three months after the 25th month of your disability.

General Enrollment Period (GEP)

If you missed your Initial Enrollment Period (IEP), you can use the GEP to get enrolled. Every year, the Medicare GEP for Parts A and B is from January 1 to March 31, and your coverage will begin the first of the month following your enrollment.

The GEP for Parts C and D is from April 1 to June 30. This coverage will not begin until July 1, regardless of when you enroll during this period.

Medicare Supplement Open Enrollment Period (OEP)

The best time to enroll in a Medicare Supplement plan may be your Medicare Supplement OEP. This period lasts six months and begins the first day of the month in which you are both 65 or older and enrolled in Medicare Part B.

Special Enrollment Period (SEP)

You may be able to join or switch plans under special circumstances, including:

  • If you enroll in Elderly Pharmaceutical Insurance Coverage (EPIC)
  • When you lose or end your employer-sponsored coverage
  • If you make a permanent move into or out of your plan’s service area
  • If you become approved for Low Income Subsidy (LIS – “Extra Help”)
  • If you qualify for any other exceptional conditions determined by the Centers for Medicare & Medicaid Services (CMS)

If you qualify for an SEP, you have two full months after the month of your qualifying event to join or change coverage outside of Part A and Part B.

What If You’re Working Past 65?

When eligible for Medicare, some people decide to remain on their employer-sponsored health insurance, or to continue working past 65 because they’re not ready to retire. Everyone’s situation is unique, so please review the information below and speak with your employer.

Even if you choose to keep working and have employer-sponsored coverage, you should generally opt-in to Medicare Part A when you turn 65, as there is no premium if you or your spouse contributed to Medicare payroll taxes for 10 years.

Part B Enrollment Past 65

Part B enrollment is more complex and is based on the size of your employer.

Employer with 20+ employees

You can wait to enroll in Medicare Part B because your employer insurance will still be the primary payer. To avoid potential penalties later, be sure to ask your employer if the prescription drug coverage provided with your plan is “creditable,” meaning it covers at least as much as Medicare Part D.

Part B Special Enrollment Period (SEP):

You can enroll in Medicare Part B during the eight-month period after your employer-sponsored health coverage or employment itself ends, whichever comes first.

SEP rules do not apply if employment or employer-provided health plan coverage ends during your Initial Enrollment Period (IEP). In addition, if you have COBRA coverage or a retiree health plan, that’s not considered coverage based on current employment, so you are not eligible for a Part B SEP when that coverage ends. In these instances, you should enroll in Part B during your IEP.

Employer with fewer than 20 employees

When you become eligible for Medicare, you should enroll in Part A and Part B because Medicare will be your primary insurance. If you do not enroll in Medicare, it will be as if you do not have any coverage, and you risk paying late enrollment penalties later on that will last the rest of your life.

Part A Late Penalty

If you have to pay a premium for Part A, and you don’t enroll when you’re first eligible, the penalty will be 10% of your monthly premium. You’ll pay the increased premium for twice the number of years you didn’t enroll after becoming eligible.

Calculating Part A Penalties

For example, if you delayed enrollment for three years, you'll pay the penalty for six years.
3 year delay time 2 equals 6 years of penalty

Part B Late Penalty

If you didn’t enroll in Part B when you were first eligible, your monthly premium will increase by 10% for each 12-month period in which you didn’t enroll. This can become a large financial burden, as this penalty will last the rest of your life.

Calculating Part B Penalties

For example, if you delayed your enrollment for two years, you’ll have to pay a 20% higher monthly premium for as long as you have Part B.
10% of Part B premium times 2 years of delay equals 20% monthly penalty

Part D Late Penalty

If you don’t have other creditable drug coverage when you become eligible for Medicare, you have 63 days to enroll in Part D (or a plan that includes it). For each full month after this that you delay enrollment, you will pay an additional 1% of the national base beneficiary premium ($34.70/month in 2024). This penalty will last as long as you have Part D.

Calculating Part D Penalties

For example, If you delayed enrollment in Part D for 24 months, you’ll pay an additional 24% of the national base beneficiary premium, rounded to the nearest $0.10. For 2024, this penalty example would be $8.30/month.
$32.74 national base beneficiary premium times 1% time 24 months equals $8 a month monthly penalty

How Do You Switch Your Medicare Plan?

Even if you’re already enrolled in a Medicare plan, it’s wise to check regularly that you’re getting all the benefits you need and have the right coverage for you. One place to start is by reviewing your Annual Notice of Change (ANOC).

Annual Notice of Change (ANOC)

The ANOC is a notice you receive from your Part C or Part D insurance company in late September each year. This document provides a summary of any changes to the plan’s costs and coverage that will take effect January 1 of the next year.

If you’re happy with your current Medicare plan, you don’t need to do anything. But if you find that switching makes sense, there are periods available for you to do so.

Annual Election Period (AEP)

The AEP runs from October 15 to December 7 of each year, and your coverage would begin on January 1 of the following year. During the AEP, you can:

  • Change your Medicare Advantage plan (Part C)
  • Change your stand-alone prescription drug plan (Part D)
  • Add or drop prescription drug coverage
  • Return to Original Medicare (Part A and Part B)

Medicare Advantage Open Enrollment Period (OEP)

The Medicare Advantage OEP runs from January 1 to March 31 each year. The OEP allows individuals enrolled in a Medicare Advantage plan to make a one- time change to another Medicare Advantage plan or Original Medicare.

Special Enrollment Period (SEP)

If you qualify for an SEP, not only does it allow you to enroll in Medicare for the first time, but SEPs also entitle you to switch between plans if you are already enrolled in Medicare. Please see the Special Enrollment Period section for more information.

Ready to Enroll? Our Team Is Here to Help

Excellus BCBS is here to support you and help keep Medicare enrollment simple. We’ve been working to make health coverage more accessible and affordable for everyone in our community for nearly 90 years, and our local Medicare Consultants are available to help you with all things Medicare.

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Excellus BlueCross BlueShield is an HMO plan and PPO plan with a Medicare contract. Enrollment in Excellus BlueCross BlueShield depends on contract renewal. Submit a complaint about your Medicare plan at or learn about filing a complaint by contacting the Medicare Ombudsman. Y0028_9775_C.

This page last updated 10-01-2023.


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