Medicare enrollment periods, explained

Why the windows matter

Medicare is not one big open door. It is a series of specific windows, each for a specific purpose. Some of them come with lifelong penalties if you miss them, and some of them only come around once. Knowing which window applies to you is most of the battle.

Your Initial Enrollment Period (turning 65)

Your first window is seven months long: the three months before the month you turn 65, your birthday month, and the three months after. This is when most people sign up for Medicare Part A (hospital) and Part B (medical).

If you sign up before your birthday month, coverage starts the first of your birthday month. If you sign up during or after it, coverage starts the first of the following month.

If you are still working at 65

If you (or your spouse) are still working and you have health coverage through that employer, and the employer has 20 or more employees, you can generally delay Part B without penalty. When the job or the coverage ends, you get an eight-month Special Enrollment Period to sign up.

Two cautions here. COBRA does not count as active employer coverage for this purpose — the eight-month clock starts when employment ends, not when COBRA ends. And smaller employers (under 20 employees) work differently: Medicare usually needs to be in place. If this is your situation, it is worth a conversation before you decide anything.

The Medigap open enrollment window (one time only)

This is the one people most often learn about too late. When you are 65 or older and first enrolled in Part B, you get a six-month window during which you can buy any Medigap plan sold in Florida regardless of your health. No medical questions that can be used to turn you down, no extra charge for health conditions.

After that window closes, insurers in Florida can generally ask health questions and can decline you or charge more. It does not renew every year. If a Medigap plan is part of your plan, this window is the time. There is more detail in When to enroll in Medigap.

Annual Enrollment Period: October 15 – December 7

This is the window you hear advertised every fall. It is for Medicare Advantage and Part D prescription drug plans: joining one, switching, or dropping one. Changes take effect January 1.

Two things it is not. It is not a window for buying a Medigap plan without health questions — that was the one-time window above. And doing nothing is a choice too: your current plan generally rolls over, but plans change their costs and coverage from year to year, so it is worth checking the paperwork your plan sends each fall.

Medicare Advantage Open Enrollment: January 1 – March 31

If you are in a Medicare Advantage plan and it is not working out, this window lets you make one change: switch to a different Medicare Advantage plan, or go back to Original Medicare (and add a Part D drug plan). Keep in mind that returning to Original Medicare does not guarantee you can get a Medigap plan without health questions — that depends on your situation.

The General Enrollment Period: January 1 – March 31

If you missed your Initial Enrollment Period and do not qualify for a Special Enrollment Period, you can sign up for Part B between January 1 and March 31 each year, with coverage starting the month after you enroll. This is also where the late enrollment penalty shows up: Part B premiums go up about 10% for each full year you could have had Part B but did not, and that increase lasts as long as you have Part B. Part D has its own penalty that works month by month. These penalties are the reason the earlier windows matter so much.

Special Enrollment Periods

Life events open their own windows: losing employer coverage, moving out of your plan’s service area, and several others. Each has its own rules and deadlines, usually shorter than you would expect. If something in your life just changed, do not assume you have until fall — check.

If you want free, unbiased counseling on any of these windows, call 1-800-MEDICARE or contact your local SHINE office (Serving Health Insurance Needs of Elders), Florida’s free counseling program for seniors.

Want to talk it through?

If you are not sure which window applies to you, I am happy to help you sort it out — that conversation is usually short, and it can save you from a penalty that lasts for years. Get in touch — no pressure, no obligation.