The short answer: most people should enroll during their Initial Enrollment Period, the 7-month window that opens 3 months before their 65th birthday month. If you are still working at 65 with health coverage from an employer with 20 or more employees, you can usually delay Part B without penalty, then use an 8-month special window when that employment ends. Miss your window and the late penalties follow you for life.

Here is how the windows actually work, without the mailer-pile confusion.

What is the Initial Enrollment Period?

Your Initial Enrollment Period runs 7 months: the 3 months before your birthday month, your birthday month, and the 3 months after. Sign up in the 3 months before your birthday month and coverage starts the first day of your birthday month. Sign up during or after it and coverage starts the first of the following month.

If you are already drawing Social Security, Parts A and B start automatically and your card shows up in the mail. Everyone else applies through Social Security online, by phone, or at the office.

Can I delay Medicare if I am still working at 65?

Often, yes. If you have health coverage through your own or your spouse’s active employment, and the employer has 20 or more employees, that coverage pays first and you can delay Part B without penalty. Many people in this situation still take Part A at 65 since it is premium-free for most workers, though you should skip Part A if you want to keep contributing to an HSA.

When that employment or the coverage ends, whichever comes first, you get a Special Enrollment Period: 8 months to pick up Part B with no penalty, and 2 months for a drug plan.

Two traps we see all the time at our office in Sumter:

  • COBRA does not count. It is not coverage from active employment. Your 8-month clock started when you stopped working, not when COBRA ends.
  • Small employers flip the rules. Under 20 employees, Medicare pays first. Skip Part B and you may be paying the bills Medicare would have covered.

What happens if I miss my enrollment window?

You wait, and you pay more, permanently.

  • General Enrollment Period: January 1 through March 31 each year, with coverage starting the month after you sign up.
  • Part B late penalty: an extra 10 percent of the premium for each full 12-month period you went without it, for as long as you have Part B.
  • Part D late penalty: about 1 percent of the national base premium for each month you went without drug coverage or other creditable coverage.

There is one more window worth circling: your Medigap open enrollment. For 6 months after your Part B takes effect, you can buy any Medicare Supplement plan sold in South Carolina with no health questions. After that, insurers can decline you or charge more based on health. More on that choice in Medicare Advantage vs Medicare Supplement in South Carolina.

What about the October to December enrollment I keep hearing about?

That is the Annual Enrollment Period, October 15 through December 7. It is for people already on Medicare who want to change Medicare Advantage or drug plans for the following year. It is not the window for first-time enrollment, and it does not rescue a missed Initial Enrollment Period.

How do I get help with this locally?

Enrollment timing is personal: your work situation, your spouse’s coverage, your HSA, and your prescriptions all change the right answer. Our team at Griffin Insurance in Sumter walks South Carolinians through this every week, at no cost to you, whether you are in Sumter, near Shaw AFB, or anywhere else in the state. Call or text 803-848-0089 and we will map your dates in one conversation.

Frequently asked questions

Am I enrolled in Medicare automatically at 65? Only if you are already receiving Social Security or Railroad Retirement benefits before 65. Everyone else has to sign up through Social Security.

Does COBRA count as employer coverage for delaying Medicare? No. COBRA and retiree plans are not coverage from active employment, and relying on them past 65 is one of the most common and expensive Medicare mistakes.

What if my employer has fewer than 20 employees? Medicare generally pays first, so most people need to enroll at 65 even while working. Check with us or your plan before deciding.

Are the late penalties permanent? For most people, yes. They are added to your premium for as long as you keep the coverage.

Griffin Insurance Agency is not connected with or endorsed by the United States government or the federal Medicare program. We do not offer every plan available in your area. Any information we provide is limited to those plans we do offer in your area. Please contact Medicare.gov or 1-800-MEDICARE to get information on all of your options.