Quick answer: The California birthday rule gives people who already have Medigap a yearly window of at least 60 days, starting on their birthday, to change policies without medical underwriting. It rests on three conditions: you hold a current policy, you apply inside the window, and the replacement offers equal or lesser benefits. Most people use it to buy the same coverage from a lower-priced insurer.

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What you should also be asking:

• What should you know about Medicare before you turn 65?
• When does your health insurance end after you leave a job?
• What happens if you stop paying your health insurance premium?
• Why buy travel insurance for your next trip?
• Which coverage benefits might you be missing out on?

What the Rule Lets You Do Each Year

California lets current Medigap policyholders replace their supplemental Medicare coverage once a year without answering health questions. The window opens on your birthday and lasts at least 60 days. During that time, an insurer can’t turn you down or charge you more because of your health. The one condition is that the replacement can’t cover more than your current one.

Medigap (Medicare Supplement insurance) is a supplemental insurance plan that pays some out of pocket costs left by Original Medicare’s hospital and medical insurance, like coinsurance and deductibles. Medigap policies sold after 2005 don’t include drug coverage, so you’d get that from a separate Part D plan. Our guide to the basics of Medicare coverage explains how it fits with Parts A through D.

Outside a protected window, insurers can usually review your health history before approving a voluntary change, and they can decline you. California’s yearly window lets you shop on price instead.

How It Compares to Your Federal Medigap Open Enrollment Period

The federal Medigap window is a one-time, 6-month period that begins when you’re 65 or older and enrolled in Part B. California’s birthday window works differently. It comes back each year, but it only helps people who already have Medigap coverage.

Who Qualifies and Who Doesn’t

You qualify if you live in California and have an active Medigap plan when your birthday arrives. Your age, your health, and the company that sold you the plan don’t change that.
You generally qualify if you:

• Have Medigap coverage in force on your birthday
• Apply during the window that starts on your birthday
• Choose a plan with the same or fewer benefits

You generally don’t qualify if you:

• Have Original Medicare with no Medigap
• Are enrolled in a Medicare Advantage plan (Part C) instead
• Want a plan that covers more than your current one

Limits Worth Knowing Before You Apply

California’s yearly window is a right to switch, not a right to buy. It won’t help you get Medigap for the first time. It also won’t move you into a plan with richer benefits. An insurer may accept an upgrade, but it can review your health first.

When Your 60-Day Window Opens and Closes

The window starts on your birthday and runs for at least 60 days. For example, if your birthday is March 10, it opens that day. Counting March 10 as day one, day 60 lands on May 8.

Two details help you plan. Your current insurer has to send you a notice about this right before your birthday, and it often lists the dates the insurer uses. The protected window starts on your birthday, not before. If a new insurer offers to take your application early, ask it to confirm in writing that it’s treating the switch as a birthday-window application.

What “Equal or Lesser Benefits” Means in Practice

The phrase means your new coverage can’t pay for anything your current plan doesn’t. Medigap plans are standardized by letter, so comparing letters is the simplest check. The same letter is equal. A letter that pays for fewer costs is lesser.

Here’s how three popular letters compare:

By this chart, moving from F to G or from G to N is a step down. Moving from N to G adds benefits, so the yearly window wouldn’t protect it.

Moving to the Same Plan Letter With a Different Insurer

Buying your current letter from another company is the cleanest way to use the window. Plan G from one insurer pays for the same things as the same letter from another. What changes is the monthly premium, how the company raises prices over time, and which discounts it offers.

Most people start by comparing their letter across insurance carriers. Our page on the Medigap plans we can quote lists the options available in California.

A Note on Plans C and F

Plans C and F aren’t sold to people who became eligible for Medicare on or after January 1, 2020. If you were eligible earlier and already have Plan F, you may be able to move to another insurer’s Plan F. That depends on whether the new company still sells it.

Steps to Change Plans Without a Coverage Gap

The safest order is to secure your new policy before you cancel the old one. Canceling first can leave a gap in your health coverage and no way to qualify.

1. Find your current letter and premium on your policy or bill.
2. Watch for your insurer’s birthday notice and note the dates.
3. Compare your letter from several insurance companies to determine your savings.
4. Apply after your birthday and inside the window, and say you’re using this right.
5. Keep your old policy active until the new one takes effect and you’ve decided to stay with it.
6. Cancel the old policy in writing and save the confirmation.

For more ways to get value from coverage you already pay for, see our tips on getting the most out of your health insurance plan.

Mistakes That Can Cost You the Protection

Most failed attempts to switch plans come down to timing or plan choice. A few common missteps:

• Applying late. Once the window closes, the insurer can ask about your health history and decline you.
• Canceling first. Without active Medigap, you no longer meet the eligibility test.
• Choosing an upgrade. A plan with more benefits falls outside the protection.
• Mixing up programs. The window applies to Medigap, not to Part C plans.
• Comparing only this year’s price. A low starting premium can climb faster as you age.

Where to Get Free Help Comparing Plans

California’s Health Insurance Counseling and Advocacy Program (HICAP) offers free, confidential one-on-one Medicare counseling at 1-800-434-0222.

A licensed insurance agent can also compare premiums for your letter across companies and help you time the switch.

For a more technical breakdown, continue below.

The Law Behind California’s Annual Switching Right

Under the California birthday rule, Medicare Supplement policyholders get a yearly window set by Insurance Code $10192.11(h). The statute sets an annual open enrollment window that starts on each policyholder’s birthday. It also bars insurers from denying, conditioning, or pricing qualifying coverage based on health. A parallel rule, Health and Safety Code $1358.11(h), covers Medigap contracts from plans overseen by the Department of Managed Health Care (California Health and Safety Code $1358.11).

How the Window Grew From 30 to 60 Days

The 60-day length dates to 2020. Senate Bill 407, signed on October 7, 2019, raised the minimum window from 30 days to 60 days (California Legislative Information, SB-407). The change took effect January 1, 2020.

The current statute describes a window “lasting 60 days or more, commencing with the individual’s birthday” (California Insurance Code $10192.11). Insurers can’t use health status, claims experience, receipt of health care, or medical condition against a qualifying applicant. Any source that still describes a 30-day window predates the change.

The Notice Your Insurer Has to Send

Insurers have to tell you about your birthday right in advance. The California Department of Insurance (CDI) says companies “must advise you of this right at least 30 and no more than 60 days prior to your birthday” (CDI, Informing Seniors).

The notice gives you a head start on price shopping. It doesn’t move the start of the protected period, which still begins on your birthday.

Where Plan Comparisons Get Tricky

California law doesn’t publish a single ranking of each Medigap letter. It asks whether the new plan’s benefits are equal to or less than the old plan’s. For most moves between common letters, the answer is clear. For a few, each plan pays for something the other doesn’t. Medigap comes in 10 standardized letters (A, B, C, D, F, G, K, L, M, and N), according to Medicare.gov’s comparison chart.

Why Plan C to Plan G Isn’t a Clear Step Down

Plan C covers a deductible that G leaves to you. G pays excess charges, and C doesn’t, according to the same Medicare.gov chart. Because each plan has a benefit the other lacks, a C-to-G move may not count as equal or lesser.

Ask the new insurer or CDI about moves like this before you apply. The statute also maps older 1990-era letters to current ones. An old Plan J counts as equal to Plan F, and an old Plan E or H counts as equal to Plan D (California Insurance Code $10192.11).

Plans K and L Pay a Share, Not the Full Cost

Plans K and L split many costs with you instead of paying them in full. Plan K pays 50% of items like the first 3 pints of blood, hospice coinsurance, and skilled nursing coinsurance. Plan L pays 75% of the same items.

Both plans cap your yearly out-of-pocket spending, at $8,000 for K and $4,000 for L in 2026. Because cost-sharing differs by letter, a move between K, L, and N deserves the same check as a C-to-G move.

High-Deductible Versions and Extra Perks

Plans F and G come in high-deductible versions in some states. With these, you pay up to $2,950 in 2026 in Medicare-covered costs before the policy pays anything, per that chart. Going from a standard plan to its high-deductible version cuts what the policy pays.

Some insurers add small extras to standardized plans, such as discounts or wellness perks. California law says these “new or innovative benefits” don’t count when judging whether one plan offers more than another (California Insurance Code $10192.11). An add-on can’t make two same-letter plans unequal.

Why Identical Coverage Can Cost Different Amounts

Insurers charge different premiums for the same letter because they set and raise prices in different ways. CDI notes that Medigap plans are standardized (CDI Medigap guide). So price, rating method, and discounts are where companies differ.

Three Ways Insurers Set Medigap Prices

CDI describes three rating methods (CDI rating methodology page):

Attained-age and issue-age premiums can also rise with inflation. CDI warns that attained-age policies tend to cost less at first but can lead to much higher premiums at older ages. When you compare quotes, ask each insurer which method it uses.

What Medigap Policyholders Pay Nationally

Monthly premiums vary widely by plan and state across the Medigap insurance industry. KFF, an independent health policy research group, found the average Medigap premium among current policyholders was $217 a month in 2023. For Plan G, it was $164, with state averages from about $140 to $236 (KFF).

The same report found that 42% of people in traditional Medicare, or 12.5 million Medicare beneficiaries, had Medigap in 2022. In 2023, 39% of policyholders had letter G, 36% had F, and 10% had N.

These are national averages for existing policyholders, not California quotes. Your price depends on your age, ZIP code, tobacco use, and the insurer’s rating method.

Other Guaranteed Issue Rights in California

The birthday window is one of several guaranteed issue rights, meaning specific life events or situations where an insurer must sell you Medigap without health screening. CDI notes that California extends these rights to people who lose COBRA or CalCOBRA coverage. It also covers people who become eligible only for Medi-Cal with a share of cost (CDI Senior Advisory).

Federal rights are narrower. Medicare.gov says that in most cases you can’t switch Medigap outside your 6-month window without a guaranteed issue right. It tells readers to ask their state about extra options.

The federal window itself depends on when you sign up for Medicare. The Initial Enrollment Period lasts 7 months, starting 3 months before the month you turn 65. The General Enrollment Period runs from January 1 to March 31 each year (Medicare, when coverage starts).

Birthday rules are state specific, and a few other states offer their own versions with stricter terms. Indiana’s rule, in effect since January 1, 2026, only allows a switch to the same plan letter from a new insurer (Indiana SHIP fact sheet). Virginia’s rule, added to state law in 2025, also requires the same benefits (Code of Virginia $38.2-3611).

The 90-Day Enrollment Proposal That Didn’t Pass

Senate Bill 242 (2025 to 2026) would have created a 90-day yearly Medigap enrollment window starting each January 1. The bill stalled in the Senate Appropriations Committee. It was returned to the Secretary of the Senate on February 2, 2026 (California Legislative Information, SB-242 status). The 60-day birthday window remains the law.

Frequently Asked Questions

Can I use the birthday window if I’m in a Medicare Advantage plan?

No. The window only protects people who already have Medigap. Medicare.gov notes that when you’re getting started, you can choose Medigap or a Medicare Advantage Plan, “but you can’t have both” (Medicare, how Medigap works). Those plans work differently. Most Medicare Advantage Plans include Part D drug coverage, and you may need prior authorization before the plan covers certain services (Medicare, Original Medicare vs. Medicare Advantage). Leaving that type of plan for Medigap depends on other rules and timing. A HICAP counselor or licensed agent can check which ones fit you before you drop your current plan.

Can a new insurer make me wait for coverage of a pre-existing condition?

Not when you switch during your birthday window. CDI says you can buy a new policy in the 60 days after your birthday “without a medical screening or a new waiting period” (CDI Senior Advisory). So if you’ve been treated for a heart condition, the new policy should pay its share of related costs from its start date, just as your old one did.

What happens if I miss my window this year?

You’ll likely face medical underwriting if you try to switch before your next birthday. That means the insurer can review your health and say no. Medicare.gov warns that “if you drop your Medigap policy, in most cases you won’t be able to get it back” ( Medicare, switching or dropping Medigap). Keeping your current coverage and planning for next year is usually the safer path.

Can I use the window more than once?

Yes. The statute describes an annual period, so the right returns each year on your birthday. That’s useful if the insurer you pick this year raises its rates later. You could compare again at your next birthday and move to the same letter elsewhere.

What if I change my mind after the new policy starts?

You get a 30-day free look period. Medicare.gov says that when you get your new policy, “you have 30 days to decide if you want to keep it.” You’ll pay both premiums for the month you have both (Medicare, changing Medigap policies). CDI adds that you can return the policy within 30 days of receiving it for a full refund (CDI, Informing Seniors).

Who can I contact if an insurer won’t honor my birthday window?

Call the California Department of Insurance Consumer Hotline at 800-927-4357. CDI says its hotline staff answer questions and help consumers file complaints (CDI Medigap guide). Before you call, gather your policy, the insurer’s birthday notice, and any written denial. That lets the staff review the dates and letters involved.

Disclaimer

This article gives general information about California’s yearly Medigap switching window and related state rules. It isn’t legal or individual insurance advice. Whether you can switch depends on your current plan, the date your window opens, your insurer’s process, and how the new plan’s benefits compare to your current ones. Laws, premiums, and plan offerings change, and proposed bills don’t always become law. Before you cancel or replace a policy, confirm the dates and benefits in writing with the new insurer, and keep your current policy until the new one takes effect. Take extra care if you’re moving between different plan letters, to or from a high-deductible plan, or away from Part C coverage. For questions about your own policy, contact Harmony Health Insurance Services at 1-855-545-5858. Harmony is a licensed insurance agency and isn’t affiliated with or endorsed by the U.S. government or the federal Medicare program.

About this article.

Prepared by Harmony Health Insurance Services. It covers how California’s birthday window works, how plan letters compare, how Medigap is priced, and how the rule differs from federal rights and other states’ rules. The text was drafted with AI assistance to organize research and prepare the copy. Facts were checked against primary sources, including the California Insurance Code, the California Department of Insurance, Medicare.gov, KFF, and other state sources, and people edited and approved the final text. Written October 2026. Medigap rules and premiums change, so confirm current details before you act.

Questions about your own policy?

Susan Fujimoto is a licensed insurance agent in Santa Monica and West Los Angeles with over 25 years of experience and a Certified Insurance Agent for Covered California. She and the Harmony team can compare your current plan with other California insurers at 1-855-545-5858.