Where to sign up for a Medigap policy
You sign up for Medicare Supplement insurance directly with private insurance companies, not through Medicare itself. The companies that sell Medigap policies include major insurers like UnitedHealthcare, Humana, AARP (underwritten by UnitedHealthcare), Cigna, and Anthem, though which ones operate in your state varies. You can contact them by phone, visit their websites, or work with an independent insurance agent who represents multiple companies.
The fastest route is often an independent agent or broker, because they can compare prices across several insurers at once and handle the paperwork. You can find agents through the National Association of Health Underwriters (NAHU) website or by searching "Medicare supplement agent near me." Many agents do not charge you directly — the insurance company pays them a commission.
You can also contact insurers one at a time on your own. Call the customer service number on their website or look for their Medicare Supplement section. Have your Medicare card handy when you call, because they will need your Medicare number and birth date to quote you a price.
Key Takeaways
- Medicare Supplement policies are sold by private insurance companies, not by Medicare, and you contact the companies directly or through an independent agent.
- You have the best price protection if you sign up during your initial enrollment window — usually the six months after you turn 65 and enroll in Medicare Part B.
- Outside that window, insurers can deny you coverage or charge more based on your health history, a practice called medical underwriting.
- The same Medigap plan (for example, Plan G) covers the same things no matter which company sells it, so comparing prices between insurers is the main way to save money.
- You can switch Medigap policies at any time, but switching outside your enrollment window may require you to answer health questions again.
The enrollment window when you have the best rates
Your initial enrollment period for Medigap is the six-month window that starts the month you turn 65 and enroll in Medicare Part B. During this time, insurers must sell you any Medigap plan they offer at their standard rate, and they cannot ask health questions or deny you based on pre-existing conditions. This is called may provide issue rights.
If you miss this six-month window, you can still buy Medigap coverage, but insurers can use medical underwriting — meaning they review your health history, may ask you health questions, and can charge you more or refuse to sell you a policy. Some states have additional may provide issue windows (for example, if you lose employer coverage), but the initial six-month window is the one that applies to most people.
If you are already on Medicare and did not buy Medigap during your initial window, you can still contact insurers now. Some will sell to you without health questions; others will not. Calling to ask costs nothing, and you may find at least one company willing to cover you.
What to have ready before you contact an insurer
Gather these documents before you call or visit a website: your Medicare card (for your Medicare number), your Social Security number, your date of birth, and information about any current health insurance you have. If you are switching from one Medigap policy to another, have your current policy number and the name of your current insurer.
You will also need to decide which Medigap plan you want. Plans are labeled A through N (and G and M in some states), and each letter covers a different combination of costs. Plan G, for example, covers most of what Medicare does not, while Plan N covers less but costs less per month. Your state may not offer all plans — check your state insurance commissioner's website for a list of plans available where you live.
The insurer will ask whether you want coverage to start on a specific date. Most policies start on the first of the month, though some start mid-month. Tell them your preferred start date, and they will confirm whether that is possible.
How the enrollment process works step by step
Once you contact an insurer or agent, they will confirm your Medicare enrollment status and ask which Medigap plan you want. They will quote you a monthly premium — the price you pay each month. Premiums vary widely between insurers for the same plan, so if you are comparing, get quotes from at least three companies.
After you choose a company and plan, they will send you an process (on paper or online, depending on the company). You sign it, and the company processes it. If you are within your initial enrollment window, approval is usually quick — often within one to two weeks. If you are outside that window and the company does medical underwriting, approval can take longer, sometimes three to four weeks.
Once approved, your policy becomes active on the date you agreed to. Your first premium payment is usually due before coverage starts. Some insurers bill you monthly by automatic bank withdrawal; others send a bill. Confirm the payment method when you enroll.
Switching Medigap policies or insurers
You can switch to a different Medigap policy or a different insurance company at any time. If you switch within your initial enrollment window, the new insurer must cover you without health questions. If you switch after that window closes, the new insurer may ask health questions and can deny you or charge more.
When you switch, there is usually a gap between when your old policy ends and your new one starts. Coordinate the dates carefully so you do not have a day without coverage. Contact your new insurer first to confirm your start date, then contact your old insurer to cancel. Some insurers require written notice to cancel; others accept a phone call.
If you are switching because you are unhappy with your current insurer's customer service or claims handling, ask the new insurer about their process before you enroll. Read recent customer reviews on your state insurance commissioner's website or the National Association of Insurance Commissioners (NAIC) database.
State differences in Medigap availability
Not all Medigap plans are available in every state. Most states offer plans A, B, C, D, G, M, and N, but some offer fewer. A few states (Massachusetts, Minnesota, and Wisconsin) have their own Medigap plans that are different from the standard plans offered elsewhere. If you live in one of those states, contact your state insurance commissioner's office for a list of plans available to you.
Premiums also vary by state and by county within a state. An insurer may charge different rates depending on where you live. When you get a quote, confirm that it is for your zip code, because moving even a few miles can change your rate.
Your state insurance commissioner's office maintains a list of insurers licensed to sell Medigap in your state and their phone numbers. You can find this on your state's insurance department website by searching "[your state] insurance commissioner Medigap" or by calling your state's insurance hotline.
Frequently Asked Questions
Can I sign up for Medigap online?
Some insurers let you complete the entire process online, including filling out the process and paying your first premium. Others require you to call or mail in a paper process. Check the insurer's website to see what options they offer, or call their customer service line to ask.
What if I am still working and have employer health insurance?
You can buy Medigap while you are still working, but you do not have to. If you have employer coverage, you may want to wait until you retire and lose that coverage. When you do, you will have a may provide issue window to buy Medigap without health questions — usually 63 days after your employer coverage ends. Contact an insurer or agent to confirm the exact dates for your situation.
Do I need Medigap if I am in a Medicare Advantage plan?
No. Medicare Advantage (Part C) is an alternative to Original Medicare, and you cannot use Medigap with it. Medigap only works with Original Medicare (Part A and Part B). If you switch from Medicare Advantage to Original Medicare, you will have a may provide issue window to buy Medigap.
What happens if an insurer denies my process?
If an insurer denies you outside your initial enrollment window, they must tell you why in writing. You can appeal their decision or contact other insurers — not all companies use the same underwriting standards. Your state insurance commissioner's office can also help if you believe the denial was unfair.
Can I buy Medigap through Medicare.gov?
No. Medicare.gov has tools to compare Medigap plans and find insurers in your area, but you cannot buy directly through the site. You must contact the insurance company or an agent to enroll. Medicare.gov's Plan Finder tool is a good starting point to see which plans and insurers operate in your state.