Medicare Open Enrollment runs from October 15 to December 7 each year

Open Enrollment is the window when you can change your Medicare coverage for the following year. During these eight weeks, you can switch between Original Medicare and Medicare Advantage plans, add or drop prescription drug coverage, or change which plan you're in. Outside this window, you cannot make most changes unless you have a may have access to life event — and even then, your options are limited.

The dates are the same every year: October 15 through December 7. Any changes you make during Open Enrollment take effect on January 1 of the next year. This means if you enroll in a new plan on November 1, that plan covers you starting January 1.

If you miss the October 15 important date, you will not be able to change your coverage until the following October — with rare exceptions. The cost of waiting can be significant: a plan that costs $50 more per month than your current one will cost you $600 more over the year if you cannot switch until next October.

Key Takeaways

  • Open Enrollment happens every year from October 15 to December 7, and changes take effect January 1.
  • You can switch between Original Medicare and Medicare Advantage, change prescription drug plans, or move to a different plan within the same category.
  • If you miss the October 15 important date, you cannot change your coverage until next October unless you have a may have access to event like moving, losing employer coverage, or a major life change.
  • Medicare sends notices in September and early October listing plan changes and premium increases for the coming year — review these before Open Enrollment starts.
  • You can enroll online at Medicare.gov, by phone at 1-800-MEDICARE, or in person at a local Social Security office or senior center.

What you can and cannot change during Open Enrollment

During Open Enrollment, you can switch from Original Medicare to a Medicare Advantage plan, or from Medicare Advantage back to Original Medicare. You can also change which Medicare Advantage plan you're in, or which prescription drug plan (Part D) covers you. If you have a Medigap supplemental policy, you can switch to a different Medigap plan — though some states have restrictions on which plans will cover you depending on your age and health history.

You cannot enroll in Medicare for the first time during Open Enrollment if you are not yet 65 or do not yet have the 40 work credits required. You also cannot change your Part A (hospital insurance) or Part B (medical insurance) coverage itself — those are locked in once you enroll. What you can change is which plan delivers that coverage and what additional services come with it.

If you have employer coverage through a current job, you may not need to enroll in Medicare at all yet, and Open Enrollment does not explore to you. Once you retire and lose that coverage, you will have a Special Enrollment Period to sign up for Medicare without penalty — usually 63 days after your employer coverage ends.

How to find out what changed in your current plan

In September, Medicare mails a notice called the "Annual Notice of Change" to everyone with a Medicare Advantage or Part D plan. This document lists the plan's new premium, any changes to the doctors and hospitals it covers, and changes to which drugs are covered. Read this notice carefully — plans change every year, and a doctor you see now may not be in-network next year.

You can also view plan details on Medicare.gov starting in October. The site lets you search by your ZIP code and see which doctors, hospitals, and pharmacies are in each plan's network. If your current doctor is dropping out of your plan, or if your prescription costs are rising, Open Enrollment is when you can move to a plan that works better for you.

If you do not receive a notice by mid-September, call 1-800-MEDICARE to request one. Do not assume your plan is unchanged just because you did not hear anything — plans change whether or not you receive the notice.

How to enroll in a new plan during Open Enrollment

You have three main routes: online at Medicare.gov, by phone at 1-800-MEDICARE, or in person. Online is usually fastest — you can compare plans side by side, see your out-of-pocket costs for your current medications, and enroll when ready. The Medicare.gov plan finder tool lets you enter your doctors and prescriptions and shows you which plans cover them and what you will pay.

By phone, a Medicare representative can walk you through your options and enroll you on the call. This takes longer than online but is useful if you have questions or do not have internet access. You can also visit a local Social Security office, senior center, or library — many offer in-person help during Open Enrollment, and some have staff who speak languages other than English.

When you enroll, have your current plan information handy so you can confirm you want to leave it. You do not need to contact your old plan to cancel — Medicare handles that automatically when your new plan starts on January 1. However, if you are switching from Medicare Advantage back to Original Medicare and want Medigap coverage, you should enroll in Medigap at the same time, because waiting can cost you more in premiums.

What happens if you miss the October 15 important date

If you do not enroll during Open Enrollment, your current plan continues into the next year with whatever premium and coverage changes it has made. You cannot switch plans until the following October 15, unless you have a may have access to life event.

may have access to events include moving to a new state or ZIP code, losing employer coverage, getting married or divorced, having a baby, or experiencing a significant drop in income. If any of these happen to you, you have 60 days from the event to make changes. You must contact Medicare and provide proof of the event — for example, a lease or utility bill if you moved, or a divorce decree if you divorced.

Some people also become newly may be able to access for Medicare during the year — for example, if they turn 65 or become disabled. If that happens to you, you have a seven-month Initial Enrollment Period to sign up, and you should do so as soon as you are may be able to access to avoid late-enrollment penalties on Part B and Part D.

Common mistakes to avoid during Open Enrollment

The biggest mistake is waiting until December 6 to enroll. If you enroll in the last few days and something goes wrong — your process is incomplete, there is a processing error, or you realize you chose the wrong plan — you will not have time to fix it before January 1. Enroll by mid-November to give yourself a buffer.

Another common error is choosing a plan based on premium alone. A plan with a $0 monthly premium may have a $5,000 deductible and high copays, while a plan with a $50 premium may have a $500 deductible and lower copays. Use the Medicare.gov plan finder to see your total out-of-pocket costs, not just the premium.

Do not assume your doctor is in your new plan's network just because they were in your old one. Check the plan's provider directory on Medicare.gov or call the plan directly before you enroll. If your doctor is not listed, ask the plan if they are accepting new patients — some doctors are in-network but not taking new Medicare patients.

If you take multiple prescriptions, enter all of them into the plan finder tool. A plan may cover one of your drugs but not another, or cover it only with a high copay. Checking this before you enroll prevents surprises in January.

Frequently Asked Questions

Can I change my mind after I enroll during Open Enrollment?

Yes, but only once. If you enroll in a new plan and then change your mind, you can switch to a different plan one time before January 1. After January 1, you are locked into your choice until the next Open Enrollment, unless you have a may have access to life event. Make your final choice carefully.

What if I turn 65 during Open Enrollment?

You have a separate Initial Enrollment Period that runs for seven months — three months before the month you turn 65, the month you turn 65, and three months after. You do not have to wait for Open Enrollment. Enroll as soon as you are may be able to access to avoid late-enrollment penalties.

Do I have to enroll in Part D prescription drug coverage during Open Enrollment?

If you are on Original Medicare, Part D is optional — but if you go without it and later want to enroll, you will pay a penalty for each month you were not covered. If you do not take regular prescriptions, you can skip it, but you cannot add it later without penalty unless you have a may have access to event.

Can I enroll in Medicare Advantage if I have a pre-existing condition?

Yes. Medicare Advantage plans cannot deny you or charge you more based on your health history. You can enroll during Open Enrollment regardless of any medical conditions you have. However, some plans may have waiting periods for certain services like dialysis or transplants.

What if my plan is being discontinued?

If your current plan is ending, Medicare will notify you by September 30. You must choose a new plan during Open Enrollment — your coverage will not automatically continue. Medicare will suggest similar plans, but you should review your options to find the best fit for your doctors and prescriptions.