Every fall, a thick envelope lands in millions of mailboxes. It comes from a Medicare plan, it uses words most people never see the rest of the year, and it usually gets set on the counter with the intention of reading it later. If that envelope is sitting on your counter right now, you are not behind. You are right on time.
That envelope is your plan telling you what is changing for next year. It arrives just before the one stretch of the calendar when almost anyone on Medicare can make a change. If you have both Medicare and Medicaid, though, your options are a little different, and in a good way. You may not have to wait for that fall window at all.
Let’s walk through what the Medicare Annual Enrollment Period is, when it happens, and what it really means for you as someone with both programs.
When the Medicare Annual Enrollment Period happens
The Medicare annual enrollment period runs from October 15 to December 7 every year. Any change you make during that window starts on January 1 of the next year. So a plan you pick this fall would begin covering you at the start of 2027.
You might also hear this called the fall open enrollment or just “AEP.” They all point to the same stretch of weeks. It is the main time of year when people can join a Medicare Advantage plan, switch from one plan to another, drop a plan, or change their drug coverage.
Mark those two dates somewhere you will see them. Once December 7 passes, the general door closes for most people until the next fall.
What you can do during this window
The annual enrollment period is flexible. During those weeks you can join a Medicare Advantage plan for the first time, move from Original Medicare into an Advantage plan, switch between two Advantage plans, go back to Original Medicare, or add, change, or drop a Part D drug plan.
You do not need a reason. You do not need to explain yourself. If the coverage you have now no longer fits, this is the built in chance to fix it. For most folks on Medicare, this once a year window is the only time they can freely make these moves.
The good news if you have both Medicare and Medicaid
Here is where being a dual eligible member changes the picture. When you qualify for both Medicare and Medicaid, you usually get your own special enrollment period on top of the regular fall window. That means you often do not have to wait until October to make a change.
People who have both programs and full Medicaid benefits generally get a monthly chance to switch into a plan built for their situation. In plain terms, you may be able to make a move once a calendar month rather than once a year. When you do, the new coverage usually starts on the first day of the following month.
This matters because life does not wait for October. A doctor leaves your plan in March. A prescription stops being covered in June. Your income situation shifts. With the extra flexibility that comes with having both programs, you have room to respond when things change instead of sitting with a plan that no longer works.
How the monthly window works
A dual special needs plan, often shortened to D SNP, is a Medicare Advantage plan made for people who have both Medicare and Medicaid. If you have full benefits from both, you can generally use your monthly special enrollment period to join or switch to one of these plans, often one that lines up with the Medicaid coverage you already have.
The idea is to keep everything working together. Your Medicare and your Medicaid coordinate instead of pulling in two directions. And to be clear, joining a dual plan does not take your Medicaid away. You keep your Medicaid. The dual plan sits alongside it and pulls the pieces into one place.
When the monthly window may not apply
The monthly switching option is mainly for people with full Medicaid benefits. If you have partial Medicaid help, or you only receive Extra Help with drug costs (also called the Low Income Subsidy), the monthly window may not cover you the same way. Your enrollment timing can look different, and that is exactly the kind of detail worth checking with a real person before you act.
Rules like these shift from year to year and can depend on your county and your exact level of Medicaid. So treat the general picture here as a starting point, not a final answer for your situation.
Read your Annual Notice of Change first
Before you decide anything, go back to that envelope. Each fall, your plan sends an Annual Notice of Change. It spells out what is different for the coming year: the drugs on the list, the pharmacies in the network, the extra benefits, and any changes to what you pay.
Read it with one question in mind. Does my plan still do what I need it to do next year? If the answer is yes, you may not need to change a thing. If something important dropped off, that is your signal to look at other options, either during the fall window or through your monthly dual member window.
What to check before you switch a dual plan
Switching plans is not hard, but a few minutes of checking saves a lot of headaches later. Before you move, look at four things.
First, your doctors. Make sure the ones you want to keep are in the new plan’s network. Second, your medicines. Confirm each prescription you take is covered and see what you would pay for it. Third, the extra benefits, like help with dental, vision, hearing, transportation to appointments, or an over the counter and grocery allowance on many dual plans. Fourth, the pharmacies and any costs you would owe out of pocket.
If all four still work for you, you may be in the right place already. If not, a change during the right enrollment window can put you back on track.
A quick, honest word about benefits
You will see a lot of eye catching numbers this time of year, especially around grocery and flex card allowances. Here is the honest version. These extras are real on many dual plans, but they come as an amount up to a set limit, and only if you are eligible. They are not cash, not a check from the government, and not guaranteed to be the same from one plan or county to the next.
Any dollar figure you see is a sample that changes by plan, county, carrier, and year. The only way to know what you would actually get is to look at the specific plans offered where you live. That is a conversation worth having before the annual enrollment period ends, so you are choosing from real numbers instead of advertising.
Key takeaways
The Medicare annual enrollment period runs October 15 to December 7, and any change you make starts January 1. It is the main once a year window for most people on Medicare to join, switch, or drop a plan.
If you have both Medicare and Medicaid with full benefits, you likely get a monthly chance to switch into a dual plan, so you often do not have to wait for fall. Read your Annual Notice of Change first, check your doctors and medicines before you move, and remember that joining a dual plan does not cost you your Medicaid.
Frequently asked questions
When is the Medicare annual enrollment period in 2026?
It runs from October 15 to December 7. Changes you make take effect on January 1, 2027.
Do dual eligible members have to wait for the fall window?
Often no. If you have both Medicare and Medicaid with full benefits, you usually get a special enrollment period that lets you make a change about once a month.
Will I lose my Medicaid if I join a dual plan during enrollment?
No. You keep your Medicaid. A dual special needs plan works alongside it and helps the two programs coordinate.
What if I only have Extra Help and not full Medicaid?
Your enrollment timing may be different. It is worth checking your exact situation with a licensed insurance agent before you make a move.
See what you may qualify for
If you have both Medicare and Medicaid, you have more say over your coverage than most people on Medicare, and you do not have to figure it out alone. You can call to see if you qualify for a dual plan in your area. It is free, there is no obligation, and there is no pressure to sign up for anything.
Not sure whether you have both programs yet? Start with our simple guide on how to tell if you are dual eligible, or read more about what a dual plan is and how it works. When you are ready, a quick call can tell you what is available where you live.
Call (800) 000-0000My Dual Plan is a private information and referral service. We are not an insurance company, an agency, or a licensed producer. When you call, you are connected with a licensed insurance agent who can discuss the dual special needs plans they offer in your area. We are not affiliated with, endorsed by, or connected to Medicare, Medicaid, CMS, or any government agency. We do not offer every plan available in your area. Any information we provide is limited to the plans we do offer in your area. Please contact Medicare.gov or 1-800-MEDICARE to get information on all of your options.