AARP Eye Center
Even after you sign up for Medicare, you still have to pay deductibles and copayments for hospital stays, doctor visits and other health care expenses. If you enroll in traditional Medicare, you can buy a Medicare supplement, better known as a Medigap plan, from a private insurance company to help fill in the gaps.
But there’s a catch: If you don’t get the policy within a certain time frame, insurers in most states can reject you or charge more because of preexisting conditions. This limitation no longer exists for other kinds of health insurance.
To avoid this, find out when you can sign up and whether you might encounter any difficulties based on your health. Take the following steps to get the coverage you need:

AARP Membership — $12 for your first year when you sign up for Automatic Renewal
Get instant access to members-only products and hundreds of discounts, a free second membership, and a subscription to AARP The Magazine.
1. Sign up at the right time
You can purchase a Medigap policy regardless of whether you have any preexisting conditions — known as a guaranteed issue right — during the following times:
- For six months starting the month you sign up for Medicare Part B when you’re 65 or older. You’ll get the best price for any policy in your area based on your age, sex and smoking status.
- Up to 63 days after you’ve lost job-based health insurance that's considered secondary to Medicare. If you or your spouse works for a company with fewer than 20 employees and you’re 65 or older, your insurance is generally considered secondary to Medicare.
- During a trial enrollment period. If you sign up for a Medicare Advantage plan when you first enroll in Medicare, you have up to 12 months to drop the plan, switch to original Medicare, and get any Medigap policy in your area.
- If you dropped a Medigap policy to enroll in Medicare Advantage and want to switch back to original Medicare. You have up to 12 months to get the same Medigap policy.
- If you move out of your Medicare Advantage plan’s service area or your plan leaves the business.
For more information about the times insurers can’t charge more or reject you because of your health, see the Centers for Medicare & Medicaid Services’ Guide to Choosing a Medigap Policy.
2. Know your state’s rules
Three states — Connecticut, Massachusetts and New York — allow you to buy a Medigap policy any time regardless of your health. The private companies that issue the policies also must charge everyone the same rate regardless of age, called community rating. In these states, you can start out with a Medicare Advantage plan and pay lower premiums. Later, if you develop a health condition and want to use doctors and hospitals that aren't in the plan's network, you can switch to original Medicare and get a Medigap policy without having to pay more because of any preexisting conditions.
Maine requires insurers to offer Medigap Plan A, which offers the least amount of coverage, to anyone age 65 or older regardless of their health for one month every year. (The insurer decides which month.) Maine also extends the Medicare Advantage trial period from 12 months to 36 months. That means you have up to three years to switch back to original Medicare and get any Medigap policy.
Several states allow people who already have Medigap policies to switch plans at certain times of the year without requiring them to answer questions about their health. Insurers in most states can offer up to 10 different plans, each labeled with a letter. Plans with the same letter include the same benefits, but premiums can vary. You may be able to save money by switching to a different letter plan or a less expensive plan from a different insurer.
In Oregon, you have 30 days after your birthday each year to switch to another Medigap plan with equal or lesser benefits. In California, you have 60 days after your birthday every year to do so.
Illinois residents ages 65 to 75 starting in 2022 will be able to switch to another policy with the same insurer with equal or lesser benefits for up to 45 days after their birthday. In Missouri, you have up to 30 days before and 30 days after the anniversary of the date you purchased your policy to switch to the same letter plan with a different insurer.
In most states, insurance companies aren’t required by law to issue Medigap policies to people with preexisting conditions. However, some insurers, such as Blue Cross/Blue Shield in Illinois, do so anyway.
“People pay the same rates as anyone who is buying a policy during open enrollment,” says Sandy Leith, director of the Illinois Senior Health Insurance Program.
Tricia Neuman, executive director of the Kaiser Family Foundation’s program on Medicare policy, recently saw the differences in state rules firsthand when helping two friends shop for Medigap policies.
One friend in Pennsylvania already had a Medigap policy and wanted to switch to another plan with fewer benefits to save money. If she didn't have any health problems, the new plan each month would have cost $100 less than her current plan. But because she lives in a state that allows insurers to charge more for preexisting conditions and she uses an inhaler for a lung condition, the insurer wanted to charge $100 more than her current plan.
The experience was very different for Neuman's friend in New York. “That same company allowed a 90-year-old I know to switch plans for a lower premium,” Neuman says. She didn’t have to answer any questions about her health.
To learn about your state’s rules, contact your State Health Insurance Assistance Program. Most state insurance departments have Medigap buyers’ guides that explain the rules and may even list premiums for each insurer.