You can change Medicare Supplement plans, but only during specific windows — and the rules depend on whether you're switching between insurers or changing your coverage level.
Medicare Supplement plans (also called Medigap) are not locked in for life, but insurance companies can refuse to cover you if you switch outside the allowed periods. The main open windows are your first six months after turning 65, your plan's annual open enrollment period, and certain life events. Outside these windows, an insurer can deny you coverage or charge more based on your health history.
The timing and cost of a switch depend on your age, how long you've had your current plan, and whether your new insurer will accept you. Understanding these rules before you switch saves you from being stuck with a plan you don't want or facing a gap in coverage.
Key Takeaways
- Your first six months after Medicare starts (usually age 65) is the only time any insurer must accept you regardless of health, and this window closes permanently.
- After that window closes, you can switch plans during the annual open enrollment period (October 15 to December 7), but the new insurer can still deny you.
- Certain life events like losing employer coverage or moving to a different state may open a special enrollment window outside the standard periods.
- Switching plans usually means a new process, a waiting period for approval, and a new premium — sometimes higher than your current plan.
- If you switch outside an open window and get denied, you may be locked into your current plan until the next annual enrollment period.
The six-month window after you turn 65
When you first become may be able to access for Medicare (usually at 65), you have six months to buy any Medigap plan from any insurer, and they must accept you without asking about your health. This is called the open enrollment period for Medigap, and it is the only time in your life when you have this protection. The window starts the month you turn 65 and enroll in Medicare Part B, and it closes six months later.
If you miss this window, you lose the right to buy any plan you want. After it closes, insurers can deny you coverage, charge you more, or exclude certain conditions from coverage based on your medical history. This makes the six-month window critical — if you think you might want to switch plans later, it is safer to switch during this period even if you are happy with your current plan.
The exact dates depend on your birthday. If you turn 65 in March and enroll in Medicare Part B in March, your six-month window runs from March through August. If you delay enrolling in Part B, the window starts when you actually enroll, not when you turned 65.
Annual open enrollment and what it covers
Every year from October 15 to December 7, you can switch to a different Medigap plan or a different insurer. During this period, you can explore for any plan offered in your state. However, the insurer can still deny you, charge you more, or exclude pre-existing conditions — they are not required to accept you just because it is open enrollment.
This annual window is your main chance to switch after your first six months end. Many people use it to move to a cheaper plan, add coverage they did not have before, or switch away from an insurer with poor customer service. The new coverage usually starts January 1 of the following year, though some insurers may have different effective dates.
During open enrollment, you can also switch from a Medigap plan to a Medicare Advantage plan, or vice versa. The rules are the same — the window is October 15 to December 7, and you can make one switch. If you switch to Medicare Advantage during this period, you can switch back to Medigap during the next year's open enrollment, but you may not have the same protections against denial.
Special enrollment windows for life changes
If certain events happen outside the standard enrollment periods, you may be able to switch plans. These events include losing employer-sponsored health coverage, moving to a state where your current plan is not available, or having your current plan leave the market. You typically have 60 days from the event to switch, though the exact timeline varies by situation.
Losing employer coverage is the most common trigger. If you or your spouse had health insurance through an employer and it ends, you can switch Medigap plans within 60 days without being denied. You will need proof of the coverage loss — usually a letter from your employer or the plan administrator stating the end date.
Moving out of your plan's service area also opens a window. If your insurer does not offer plans in your new state, or if your specific plan is no longer available where you live, you can switch. You will need to show proof of your move, such as a lease or utility bill with your new address.
What happens when you switch plans
Switching plans is not automatic. You must contact the new insurer, complete an process, and wait for approval. The process usually asks about your health history, current medications, and any recent doctor visits or diagnoses. The insurer uses this information to decide whether to accept you and what to charge.
Approval typically takes two to four weeks, though it can take longer if the insurer needs more medical information. During this time, your old plan is still active and you are still paying that premium. Once you are approved, your new plan usually starts on the first of the following month, and your old plan ends.
Your new premium will likely be different from your old one. Medigap premiums vary by age, location, and the plan letter (Plan A, Plan B, Plan C, and so on). Even if you switch to the same plan letter with a different insurer, the cost may be higher or lower. Some insurers also offer discounts for paying by automatic bank withdrawal or for bundling with other insurance products.
Switching outside open windows and what denial means
If you try to switch outside an open enrollment period and without a may have access to life event, the insurer can deny your process. Denial means they will not sell you that plan, period. You cannot appeal a denial or ask them to reconsider — they straightforward will not cover you.
If you are denied, you stay on your current plan until the next annual open enrollment period in October. This can be costly if your current plan's premium is high or if the coverage does not meet your needs. Some people in this situation choose to stay on their current plan rather than risk another denial.
The only exception is if you are still within your first six months after turning 65. During that window, no insurer can deny you, so you can switch as many times as you want without risk. Once that window closes, denials become possible.
How to learn about you can switch right now
Check the current date against the annual open enrollment window (October 15 to December 7). If you are within that window, you can explore to switch plans. If you are not, ask yourself whether a recent life event qualifies you for a special enrollment window — losing employer coverage, moving, or having your plan leave the market are the main ones.
If neither applies and you are past your first six months, contact your current insurer and ask whether they will let you switch. Some insurers have their own policies that are more generous than the legal minimum. It costs nothing to ask, and the answer may surprise you.
You can also contact your State Health Insurance information Program (SHIP), which offers free counseling about Medicare insurance. SHIP can tell you whether you may have access to for a special enrollment window and which plans are available in your area. Find your state's SHIP by searching "[your state] SHIP" online or calling 1-800-MEDICARE.
Frequently Asked Questions
What if I switch plans and then change my mind?
Once your new plan starts, you are locked in until the next open enrollment period. You cannot switch back to your old plan or to a different plan until October 15. The only exception is if you discover the new plan does not cover a medication or doctor you need — in that case, contact your state's insurance commissioner's office to ask about a hardship exception.
Do I have to switch plans if my insurer raises my premium?
A premium increase alone does not may have access to you for a special enrollment window. You can only switch during the annual open enrollment period (October 15 to December 7) or if you have a may have access to life event. However, if your insurer stops offering your plan in your state, that does trigger a special window.
Can I switch from Medigap to Medicare Advantage anytime?
No. You can switch from Medigap to Medicare Advantage only during the annual open enrollment period (October 15 to December 7) or during your first six months after turning 65. Medicare Advantage has its own enrollment periods, but switching from Medigap requires using the Medigap/Medicare Advantage open enrollment window.
What if I am denied coverage when I try to switch?
Contact your State Health Insurance information Program (SHIP) to understand why you were denied and what your options are. In rare cases, your state's insurance commissioner can order an insurer to cover you if the denial was improper. Otherwise, you must wait until the next annual open enrollment period to try again.
Do I need to tell my current insurer I am switching?
No, but it is a good idea. Once your new plan is approved and has a start date, your old plan will end automatically. However, calling your old insurer to confirm the end date prevents billing errors or confusion about which plan is active.