The short answer
You switch by dropping your Medicare Advantage plan during an enrollment window, which puts you back on Original Medicare, Part A and Part B. Original Medicare has no drug coverage of its own, so you can join a separate drug plan, and you may want a Medigap policy for your share of costs.
You drop the plan in November and the change starts on January 1. Nobody sends you a drug plan on that date, and nobody sends you a Medigap policy. Original Medicare does not arrive assembled, and two clocks start running the day it does.
How do I switch from Medicare Advantage to Original Medicare?
You drop your Medicare Advantage plan during an enrollment window and you are back on Original Medicare. Two windows allow it. The Medicare Advantage Open Enrollment Period, January 1 to March 31, is open only if you already have one. Medicare Open Enrollment, October 15 to December 7, is open to everyone.
The mechanics of filing that change, and what happens if you do nothing, belong to the companion article on cancelling a plan. The windows have their own articles in the enrollment cluster.
So the act is settled quickly. The part that is not settled is where you have just landed, and whether it is finished.
What is Original Medicare, and what comes with it?
Original Medicare is Part A and Part B. You pay for services as you get them: Medicare pays part of the cost of a covered service and you pay your share. You can see any doctor or hospital that takes Medicare, anywhere in the United States.
Then there is a second half, and it is the half that catches people. Medicare.gov lists Part A and Part B as what Original Medicare includes, and directly underneath it lists what you can add. Drug coverage. And supplemental coverage to help pay your share of costs, meaning a Medigap policy, coverage from a former employer or union, or Medicaid.
Call it the Destination Is A List Of Things You Add. That naming is ours, not the government's. The list is theirs, published on the page that explains your coverage options, and reading its shape as the shape of the decision is the only thing this publication is adding.
It matters because a Medicare Advantage plan tends to arrive assembled. Most include drug coverage, and many offer extra benefits that Original Medicare does not cover, like vision, hearing and dental. Original Medicare arrives as two parts and an invitation.
That is not an argument for either one. It is what the two look like on the day you arrive, and the first item on that add list has a clock attached to it.
Do I need a separate Part D plan?
Original Medicare does not carry drug coverage, so if you want it you join a separate Medicare drug plan. Medicare drug coverage is optional and it is available to everyone with Medicare. Joining is a second, separate decision from switching.
A separate Medicare drug plan is what adds drug coverage to Original Medicare, and you need Part A or Part B, or both, to join one. Leaving a Medicare Advantage plan therefore does not remove your eligibility for drug coverage. It changes how you hold it.
Most Medicare Advantage plans include drug coverage, which is why this catches people. In most types of Medicare Advantage plan you cannot join a separate drug plan, so the coverage you had was attached to the plan you just left rather than held by you.
There is a cost to leaving the question open. You may pay a Part D late enrollment penalty if you did not join a drug plan when you first got Medicare and went 63 days or more without creditable drug coverage. The penalty goes up the longer you wait. In most cases you pay it monthly for as long as you have Part D coverage.
One detail in that rule is easy to miss and expensive. The penalty follows the person, not the plan. Medicare.gov states that you pay it for as long as you have Part D coverage even if you switch plans, so changing plans later does not reset it.
That is the fast clock, and it counts in days. The second one on the add list counts in months, and it starts from a date you may already have passed.
Will I need a Medigap policy?
Medicare Supplement Insurance, which almost everyone calls Medigap, is extra insurance from a private company to help pay your share of costs in Original Medicare. Nobody has to have one. Generally you need Part A and Part B to buy one, so leaving a Medicare Advantage plan is what makes you eligible.
There is a timing rule attached and it is worth knowing before you switch rather than after. If you do not buy a Medigap policy within 6 months of when you first get Part A and Part B, you may not be able to buy a policy, or you may pay more.
There are also situations where an insurance company cannot refuse you. Those are called guaranteed issue rights, or Medigap protections, and in most cases you have one when your other health coverage changes in some way. You may also have a trial right to try a Medicare Advantage plan and still buy a Medigap policy if you change your mind.
Whether any of those applies to you turns on your own dates rather than on a general rule, and the Medigap open enrollment article in this publication is where those dates are worked out.
Both clocks, then, are started by the same event. Which makes the date that event happens the most practical thing on this page.
When does the switch to Original Medicare take effect?
It depends which window you used, and the two do not work the same way. A change made in the Medicare Advantage Open Enrollment Period starts the first of the month after the plan gets your request. A change made in Medicare Open Enrollment starts January 1 of the next year.
| The window you used | When it runs | When the change starts |
|---|---|---|
| Medicare Advantage Open Enrollment | January 1 to March 31 | The first of the month after the plan gets your request |
| Medicare Open Enrollment | October 15 to December 7 | January 1 of the next year |
| Your first 3 months with Part A and Part B | If you joined in your Initial Enrollment Period | The month after the plan gets your request |
The difference is not cosmetic. In the January window your request date moves your start date, so a request received in February starts in March. In the autumn window it does not, and the plan must have your request by December 7.
There is a third route, and it is only for people new to Medicare. If you joined a Medicare Advantage plan during your Initial Enrollment Period, you can go back to Original Medicare, with or without a drug plan, within the first 3 months you have Part A and Part B.
If you are planning around the effective date rather than the request date, that table is the whole answer.
What this means for you
Switching is one act with a short list of consequences. You land on Part A and Part B, you can see any doctor or hospital that takes Medicare anywhere in the country, and you pay your share of each service as you get it.
Two decisions arrive with you. Whether to add a separate drug plan, which is optional but carries a lifetime penalty if you go 63 days or more without creditable coverage. And whether to buy a Medigap policy, which has a 6 month window attached to first getting Part A and Part B.
Both are worth settling before the switch rather than after, because both have dates that do not wait for you to be ready.
For how a cancellation is actually filed and what happens if you do nothing, read the article in this cluster on cancelling a Medicare Advantage plan. For the windows themselves, read the enrollment windows articles.
FAQ
What happens if I switch and then put off the drug plan decision?
The clock does not wait for you to decide. Medicare drug coverage is optional and available to everyone with Medicare, so nothing forces you to join.
But going 63 days or more in a row without Medicare drug coverage or other creditable prescription drug coverage, after you were eligible for Medicare, can bring a lifetime Part D late enrollment penalty, and Medicare.gov states the penalty goes up the longer you wait.
In most cases you pay it monthly for as long as you have Part D coverage, even if you switch plans later. There is one moment the government builds in for exactly this: drop your Medicare Advantage plan during the January to March window and you will also be able to join a separate Medicare drug plan then.
Will I automatically get drug coverage when I go back to Original Medicare?
No. Original Medicare is Part A and Part B, and Medicare.gov lists drug coverage as something you can add rather than something included.
If you want it you join a separate Medicare drug plan, which is optional and available to everyone with Medicare. This surprises people because most Medicare Advantage plans include drug coverage, so the coverage was attached to the plan rather than to you.
If you drop a Medicare Advantage plan during the January to March window, Medicare.gov states you will also be able to join a separate Medicare drug plan at that time. Going without creditable drug coverage for 63 days or more can bring a lifetime late enrollment penalty.
Do I have to buy a Medigap policy when I switch?
No, it is optional. Medigap is extra insurance sold by private companies that helps pay your share of costs in Original Medicare, and generally you need both Part A and Part B to buy a policy. The reason it comes up at the moment of switching is timing rather than obligation.
Medicare.gov states that if you do not buy a Medigap policy within 6 months of when you first get Part A and Part B, you may not be able to buy a policy, or you may pay more.
There are separate situations, called guaranteed issue rights, where an insurance company cannot deny you one. Whether your own dates give you either is the subject of this publication's Medigap open enrollment article.
What is a trial right?
Medicare.gov describes it inside its explanation of guaranteed issue rights, which are the situations where an insurance company cannot deny you a Medigap policy. In most cases you have a guaranteed issue right when your other health coverage changes in some way, such as losing that coverage.
The government's page then adds that you may also have a trial right to try a Medicare Advantage plan and still buy a Medigap policy if you change your mind.
That is the whole of what the page read states about it. The conditions, the deadlines and who qualifies are handled in this publication's article on the Medigap open enrollment period, which is the page that owns the subject.
If I switch during Medicare Open Enrollment, when am I actually on Original Medicare?
January 1 of the next year. Medicare.gov's enrollment table gives Medicare Open Enrollment as October 15 to December 7, and states that coverage starts January 1 of the next year, with the plan required to get your enrollment request by December 7. The date you send the request does not move the start date forward inside that window.
This differs from the Medicare Advantage Open Enrollment Period, January 1 to March 31, where a change starts the first of the month after the plan gets your request. So the same decision produces a different start date depending on which window you are standing in when you make it.
Can I see any doctor once I am back on Original Medicare?
Medicare.gov states that with Original Medicare you can see any doctor or hospital that takes Medicare, anywhere in the United States. The qualifier in that sentence is doing real work: the provider has to take Medicare.
The contrast the government draws is with Medicare Advantage, where it states that in many cases you can only use doctors who are in the plan's network.
The payment arrangement differs too. Under Original Medicare you pay for services as you get them, and when you get a covered service Medicare pays part of the cost and you pay your share.
Whether a specific doctor takes Medicare, and what a provider who does not accept assignment charges, have their own answers here. The one question to settle before you switch, not after, is the same one the plan you are leaving answered for you: who is going to pay for your prescriptions.
