Every autumn, Medicare beneficiaries get a chance to review and change their coverage. This period, known as Medicare open enrollment, is one of the most important dates in the American health insurance calendar, yet many beneficiaries let it pass without reviewing their plan. This guide explains when it runs, what you can change, and how to compare your options.
When Is Medicare Open Enrollment?
Medicare open enrollment, formally called the annual election period, generally runs from October 15 to December 7 each year. Changes made during this window take effect on January 1 of the following year. This timing is different from ACA Marketplace open enrollment, which typically runs from early November to mid-January, so do not confuse the two.
During this period, you can switch from Original Medicare to a Medicare Advantage plan, switch from Medicare Advantage back to Original Medicare, change from one Medicare Advantage plan to another, or join, drop, or change a Part D prescription drug plan. You can also make changes to your coverage if your health needs, medicines, or doctors have changed.
There is a separate Medicare Advantage open enrollment period early each year, generally from January 1 to March 31, during which people already in a Medicare Advantage plan can switch to another Medicare Advantage plan or return to Original Medicare. This is narrower than the fall window and does not allow someone in Original Medicare to join a Medicare Advantage plan for the first time.
What You Can Change
The fall window is broad. If you are in Original Medicare, you can join a Medicare Advantage plan that covers your area, and if you are in Medicare Advantage, you can return to Original Medicare and add a stand-alone Part D plan and, if eligible, a Medigap policy. Note that Medigap eligibility outside your initial enrollment window depends on your state's rules and your health, so returning to Original Medicare does not guarantee you can buy Medigap on the same terms.
You can also change Part D plans, which matters because formularies, the lists of covered drugs, change every year. A medicine that was covered cheaply this year may move to a higher tier or drop off the formulary next year, and switching Part D plans can save significant money.
If you are happy with your current coverage, you do not need to act. Your plan will generally renew automatically, although premiums, copayments, networks, and formularies may change. That is why even satisfied beneficiaries should read the annual notice of change their plan sends each autumn.
How to Compare Plans
Start with your medicines. List every prescription you take, including dosage, and check each plan's formulary to see whether your medicines are covered and at what tier. The Medicare plan finder tool on Medicare's official website lets you enter your medicines and pharmacies and compare total estimated yearly drug costs across plans.
Next, check your doctors and hospitals. Medicare Advantage plans use networks, and your providers may leave a network from one year to the next. Confirm that your primary care doctor, specialists, and preferred hospital remain in network for the coming year. Original Medicare, by contrast, lets you see any provider that accepts Medicare nationwide, which is a major advantage for people who travel or split time between states.
Then compare total costs: monthly premiums, deductibles, copayments or coinsurance, and the out-of-pocket maximum for Medicare Advantage plans. Original Medicare has no out-of-pocket maximum, which is why many beneficiaries pair it with a Medigap policy. Also consider extra benefits: many Medicare Advantage plans include dental, vision, hearing, fitness, or over-the-counter allowances, but weigh these against network restrictions and cost-sharing.
Reading Your Annual Notice of Change
Each autumn, your current plan must send an annual notice of change describing what will be different next year. This document is easy to ignore and important to read. It lists changes to premiums, deductibles, copayments, covered drugs, pharmacies, and provider networks.
Pay special attention to drug changes. If a medicine you rely on moves to a higher tier, your copayment could rise sharply. If a pharmacy leaves the plan's preferred network, your costs could rise even without a drug change. If your plan is being discontinued or merged into another plan, the notice will explain your options and deadlines.
If you do nothing after receiving the notice, you will generally stay in the same plan, or be mapped to a replacement plan if yours ends. Staying by default is fine if the changes are acceptable, but it is a choice, not a requirement, and comparing alternatives is worthwhile.
Common Mistakes to Avoid
One common mistake is choosing a plan based only on premium. A zero-premium Medicare Advantage plan can still have high copayments for hospital stays or specialist visits, and a narrow network that excludes your doctors. Total cost and access matter more than premium alone.
Another mistake is ignoring drug coverage. Many beneficiaries focus on medical benefits and forget to check the formulary, only to discover in January that a key medicine costs far more. Entering your full medicine list into the plan finder each autumn prevents this surprise.
A third mistake is missing the December 7 deadline. After it passes, your options narrow sharply until the next open enrollment period, except for the limited Medicare Advantage open enrollment period early in the year or a special enrollment period triggered by events such as moving or losing other coverage.
Finally, be cautious with marketing. You may receive many advertisements, calls, and mailings during open enrollment. Use official sources, such as Medicare's website and your state's health insurance assistance program, which offers free, unbiased counseling, rather than relying on sales calls alone.
Conclusion
Medicare open enrollment, from October 15 to December 7 each year, is your annual opportunity to make sure your coverage still fits your health, medicines, doctors, and budget. Compare drug formularies, check networks, read your annual notice of change, and look beyond the premium to total cost. A careful review each autumn takes an hour or two and can save money and frustration for the whole year ahead.
Frequently Asked Questions
Do I have to change my plan during Medicare open enrollment?
No. If your plan still fits, you can stay. But premiums, formularies, and networks change yearly, so reviewing your options is strongly recommended even if you ultimately stay put.
Can I switch from Medicare Advantage back to Original Medicare?
Yes, during fall open enrollment. Note that buying a Medigap policy afterward depends on your state's rules and may involve medical underwriting outside your initial enrollment window.
What is the Medicare Advantage open enrollment period?
It generally runs January 1 to March 31 and lets people already in a Medicare Advantage plan switch to another Medicare Advantage plan or return to Original Medicare. It is narrower than the fall window.
Where can I get free help comparing plans?
Your State Health Insurance Assistance Program offers free, unbiased counseling, and Medicare's official plan finder tool lets you compare plans using your own medicines and pharmacies.