The short answer is that traditional Medicare coverage IS transferrable from state to state but that Medicaid coverage is NOT transferrable from one state to the other. But there are
several parts to Medicare, so the full answer is a little bit more complicated.
Let's take Medicaid first. Each state runs its own Medicaid program. The eligibility rules -- income and assets -- are very similar for each program but not exactly the same. Also, the coverage provided differs from state to state. So, if you are enrolled in Medicaid in one state but move to another, you have to apply all over again for Medicaid coverage in the new state, this time with the new state's own Medicaid agency. Chances are good that if you've qualified in one state, you'll also qualify in the new state, but you have to file a new application.
Now, let's move on to Medicare. Traditional Medicare -- Medicare Part A (hospital insurance) and Medicare Part B (medical insurance)](https://www.caring.com/articles/medicare-part-b) -- provide the same coverage wherever you are in the United States. If you have this traditional Medicare coverage and you move to another state, you do not have to do anything to keep up your coverage. However, if you also have Medigap private insurance as a supplement to Medicare coverage, you have to notify your insurance carrier of your change of address, and the insurance company may have the right to charge you a higher monthly premium if medical costs are higher in the state you move to.
A significant portion of people with Medicare receive their coverage not from traditional Medicare Part A and Part B but instead through a Medicare Part C Medicare Advantage plan, which provides both inpatient and outpatient coverage under one insurance umbrella. These plans are not usually portable from one state to another, so if you are enrolled in one of these plans and move, you'll have to consider whether you want to enroll in a similar Medicare Advantage plan in your new state or return to traditional Part A and Part B Medicare.
Finally, if you have a Medicare Part D prescription drug plan, you may have to enroll in a new plan in the state where you move to. Check with your current plan to see if it is transferrable to your new state, and if so what changes there might be in your costs or coverage. If the plan is not available in your new state, or you don't like its new costs, you would have to consider enrolling in a new plan.