AEP runs from October 15 to December 7 each year
Annual Enrollment Period (AEP) is the one time each year when you can change your Medicare coverage without a penalty. It always starts on October 15 and ends on December 7. Any changes you make during AEP take effect on January 1 of the following year.
This is different from the Initial Enrollment Period you use when you first turn 65 or become may be able to access for Medicare. AEP is your yearly window to switch between Original Medicare and Medicare Advantage, change prescription drug plans, or add or drop supplemental coverage.
If you miss AEP, you cannot change your plan until the next October 15 — with rare exceptions. That is why marking your calendar now matters, even if you are not planning to switch.
Key Takeaways
- AEP happens every year from October 15 through December 7, and changes take effect January 1.
- You can switch from Original Medicare to Medicare Advantage, change prescription drug coverage, or add supplemental insurance during this window only.
- Missing AEP means you are locked into your current plan for the rest of the year unless you have a may have access to life event.
- Your new plan's rates, coverage, and doctor networks often change each year, so reviewing your options annually is important even if you were satisfied last year.
- You can compare plans and make changes online at Medicare.gov, by phone, or with help from a State Health Insurance information Program (SHIP) counselor at no cost.
Why you should review your coverage every October
Even if you have been happy with your plan, the details change every year. Insurance companies adjust premiums, deductibles, and copays. They add or remove doctors and pharmacies from their networks. Prescription drug formularies — the list of medications covered — shift regularly. A drug you take today might move to a higher cost tier next year, or a doctor you see might leave the network.
Medicare also updates its rules and coverage each year. Reviewing your options during AEP means you catch these changes before they affect your care. A plan that made sense in 2023 might cost you hundreds more in 2024.
If you have not looked at your coverage since you first enrolled, AEP is the time to do it. Many people stay in their original plan out of habit, not because it is still the best choice.
What you can change during AEP
During AEP, you can switch from Original Medicare (Parts A and B) to a Medicare Advantage plan, or from Medicare Advantage back to Original Medicare. You can change your prescription drug plan (Part D) to a different one, even if you stay with the same type of coverage otherwise. You can add a Medigap supplemental policy if you are on Original Medicare, or drop one if you already have it.
You cannot change your basic Medicare coverage (Parts A and B) during AEP — that is set when you first enroll. But you can change everything else around it.
If you are in a Medicare Advantage plan and want to switch to a different Medicare Advantage plan, you can do that during AEP. The same applies to prescription drug plans: you can move from one Part D plan to another.
How to make changes during AEP
You have three main routes: online at Medicare.gov, by phone with Medicare, or in person with a counselor.
The online method is fastest. Go to Medicare.gov, sign in to your account, and use the plan comparison tool. You can see side-by-side costs, coverage, and networks for plans available in your area. When you find one you want, you can enroll right there. Changes made online usually take effect within a few days.
If you prefer to talk to someone, call Medicare at 1-800-MEDICARE (1-800-633-4227). Representatives can walk you through your options and enroll you over the phone. Wait times are often long in October and November, so call early in the day or in September if possible.
For free, personalized help, contact your State Health Insurance information Program (SHIP). SHIP counselors are trained to review your specific situation — your doctors, medications, and budget — and recommend plans that fit. You can find your state's SHIP by calling 1-800-MEDICARE or visiting shiptalk.org. Many SHIP offices offer in-person appointments in October and November.
What happens if you miss the October 15 important date
If AEP ends on December 7 and you have not made a change, you are locked into your current plan for the entire next year. You cannot switch plans, add coverage, or drop coverage until the following October 15.
There are exceptions, called may have access to life events. These include losing employer coverage, moving to a new state, getting married or divorced, or having a significant change in income. If a may have access to event happens, you have 60 days from the event to make a change. You will need to report the event to Medicare and provide proof — such as a letter from your employer or a divorce decree.
Turning 65 and enrolling in Medicare for the first time is also an exception. Your Initial Enrollment Period is seven months long and does not follow the AEP calendar.
Important dates and reminders
AEP is always October 15 to December 7. Mark this on your calendar now. If you receive a Medicare Summary Notice or Annual Notice of Change from your insurance company, read it carefully — these arrive in September and October and explain what is changing in your plan for next year.
Your new coverage starts January 1, so any changes you make in October or November take effect on that date. If you switch plans, your old plan ends on December 31. Make sure you understand your new plan's rules before January 1 arrives.
If you are turning 65 in the coming months, your Initial Enrollment Period is different from AEP. You have seven months to enroll, centered on your birth month. Do not wait for October 15 if you are newly may be able to access.
Questions to ask your current plan before AEP
Before you start comparing options, gather information about what you are paying now. Pull your insurance card and recent bills. Write down the monthly premium, annual deductible, copays for doctor visits and prescriptions, and your out-of-pocket maximum. List the doctors and pharmacies you use regularly.
Then ask yourself: Did I hit my deductible this year? Did I pay more than I expected? Did any of my doctors leave the network? Did my medications get more expensive? If you answer yes to any of these, it is worth comparing other plans.
When you look at new plans, compare the total cost for a year, not just the premium. A plan with a lower monthly premium might have higher copays that cost you more overall. Use the Medicare plan comparison tool to estimate your costs based on the doctors and medications you actually use.
Frequently Asked Questions
Can I change my plan more than once during AEP?
Yes. You can make multiple changes during the enrollment period, but only your final choice will take effect on January 1. If you enroll in Plan A on October 20 and then switch to Plan B on November 15, Plan B is what you will have starting January 1. There is no penalty for changing your mind during AEP.
What if I do not receive a notice from Medicare or my insurance company?
You are still responsible for knowing when AEP is and making changes if you want to. Do not wait for a notice. Set a reminder for October 1 to review your coverage. You can check Medicare.gov anytime to see what plans are available in your area and what your costs would be.
Do I have to make a change during AEP?
No. If you are happy with your current plan and nothing has changed, you can do nothing and stay enrolled. Your coverage continues automatically into the new year. But it is still worth reviewing your plan's Annual Notice of Change to make sure there are no surprises.
Can I switch back to my old plan if I do not like my new one?
Only during the next AEP, which starts October 15. If you switch plans in November and regret it by February, you cannot change again until October. This is why it is important to compare carefully before you enroll and to understand your new plan's rules before January 1.
What if I am still working and have employer coverage?
If you are covered by an employer plan, you may not need to enroll in Medicare right away, and AEP rules may be different for you. Talk to your employer's benefits department and to Medicare before AEP to understand your options. Delaying Medicare enrollment while you have employer coverage can affect your premiums later.