Medicare Open Enrollment: What You Need to Know in 2025

Every year from October 15 through December 7, Medicare beneficiaries get a chance to take a fresh look at their coverage. This window is called the Annual Enrollment Period (AEP), or more commonly, Medicare Open Enrollment. It's the one time of year most people can make meaningful changes to their Medicare plan — and the choices you make take effect on January 1.

What you can change during Open Enrollment

Open Enrollment is broader than most people realize. During this window you can:

• Switch from one Medicare Advantage (Part C) plan to another.
• Drop a Medicare Advantage plan and return to Original Medicare.
• Join, drop, or change a stand-alone Part D prescription drug plan.
• Move from Original Medicare into a Medicare Advantage plan.

Carriers update their plans every year — premiums shift, drug formularies change, doctors leave networks, and new benefits like dental, vision, or over-the-counter allowances get added or removed. The plan that was perfect for you last year may not be the best fit for next year.

What doesn't change during Open Enrollment

One important exception: Medicare Supplement (Medigap) plans are not part of AEP. You can apply for a Medigap policy any time of year, but outside your original 6-month Medigap Open Enrollment window (which starts when you're 65 and enrolled in Part B), carriers can ask health questions and decline you based on medical underwriting.

Tips for reviewing your plan

1. Read your Annual Notice of Change (ANOC). Carriers mail it in September. It lists every change for the upcoming year.
2. Check your drug list. Make sure every prescription is still covered and the tier hasn't changed.
3. Confirm your doctors and hospitals are still in network — for Medicare Advantage plans especially.
4. Compare total cost, not just premium. A $0 premium plan can still cost more out of pocket if copays and deductibles are high.

Reviewing your plan every year is one of the simplest ways to keep more money in your pocket and make sure your coverage still matches the way you actually use healthcare.