10/30/2026
Medicare open enrollment runs through December 7, and this is the time of year many people consider switching from Original Medicare with a Medigap supplement to a Medicare Advantage plan. The lower premium can be appealing.
Before making that switch, it helps to understand one rule: in most states, moving to Medicare Advantage is much easier than moving back.
Here's why. When you first enroll in Part B at 65 or older, you get a six-month Medigap Open Enrollment Period. During that window, insurers must sell you any Medigap policy they offer, at their standard price, regardless of your health.
Once that window closes, the protection generally ends. If you leave Medigap for Medicare Advantage and later want to return, insurers in most states can review your health history, charge more, or decline to cover you.
There are exceptions worth knowing.
The trial right. If you join Medicare Advantage when you're first eligible, or drop a Medigap policy to try Medicare Advantage for the first time, you generally have 12 months to switch back to Original Medicare with guaranteed access to Medigap.
State rules. A handful of states, including California, New York, and Connecticut, give residents additional rights to change Medigap coverage.
Plan exits and moves. If your Medicare Advantage plan leaves your area, or you move out of its service area, you may gain guaranteed issue rights.
None of this means one option is better than the other. Medicare Advantage works well for some people, and Original Medicare with Medigap works better for others. It depends on your health, your doctors, where you travel, and how much cost certainty you want. What matters is knowing which Medicare decisions can be reversed later and which can't.