Medicare Enrollment Periods Explained: AEP, OEP, SEP | Medcora
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Guide · Enrollment windows

When can you actually switch? Meet the five windows.

Medicare only lets you enroll or change plans during specific windows. Miss the right one and you can be stuck for a year, or pay a penalty for life. Here they are, in plain English.

Around your 65th birthday

Initial Enrollment Period (IEP)

Seven months: three before your birthday month, your birthday month, and three after. Your first and best chance to get it right. Full walkthrough: the Turning 65 guide.

Oct 15 to Dec 7, every year

Annual Enrollment Period (AEP)

Anyone with Medicare can switch Advantage plans, move between Advantage and Original Medicare, or change Part D. New coverage starts January 1. The busiest and most important stretch of the Medicare year.

Jan 1 to Mar 31

Advantage Open Enrollment (OEP)

Already on an Advantage plan and having second thoughts? You get one switch, to another Advantage plan, or back to Original Medicare plus a Part D plan. One move, so make it count.

After life events

Special Enrollment Periods (SEP)

Moving to a new service area, losing employer coverage, qualifying for Extra Help or Medicaid, your plan leaving your county. Each opens its own window with its own clock. When life changes, call before assuming you're stuck.

6 months from Part B start

Medigap Open Enrollment

Your one guaranteed window to buy any Medicare Supplement with no health questions. After it closes, insurers in most states can decline you or charge more based on health. California and Nevada add annual "birthday rule" switches. We track those for you.

Which one are you in right now?

Tell us your birthday month and coverage situation, and we'll tell you your exact window and deadline, in one call.

Call 909-755-6037 →

Questions, answered

Can I switch my Medicare plan any time I want? +

No, outside your enrollment windows, changes are locked except through Special Enrollment Periods. The good news: between AEP, OEP, and SEPs there's almost always a legitimate path. We find it.

What's the difference between AEP and OEP? +

AEP (October 15 to December 7) is open to everyone on Medicare and lets you rethink as many times as you want until December 7. OEP (January 1 to March 31) is only for people already on a Medicare Advantage plan and allows exactly one switch.

I'm moving to another state. What happens to my plan? +

Moving out of your plan's service area triggers a Special Enrollment Period. We're licensed in Arizona, California, Florida, Nevada, North Carolina, and Texas. If you're moving between them, one call and we handle the whole transition.

Not sure which window you’re in?

One call settles it, and if you’re locked until AEP, we’ll set a reminder and call you when it opens.

Start my plan match Call 909-755-6037