California Medicare Supplement Plans

The California Birthday Rule: your yearly right to switch

California is one of a small number of states that gives Medicare Supplement policyholders an annual, no-questions-asked window to change plans. It is called the Birthday Rule, and most Californians who have a Medigap policy have never heard of it.

How it works

If you already have a Medicare Supplement policy, you get a 60-day window that starts on your birthday each year. During that window you can switch to a new Medigap policy with no medical underwriting, no health questions, and no new waiting period for pre-existing conditions.

What you can switch to

• The same lettered plan you have now, with any carrier. If you have Plan G with one company and another company has a lower Plan G rate, you can move.
• Any Medigap plan with equal or fewer benefits than the one you have now.

You cannot use the Birthday Rule to move up to a richer plan. Plan G to Plan N is allowed. Plan N to Plan G is not.

Two details that trip people up: extra “innovative” benefits some carriers bundle in, like dental or vision riders, do not count as greater benefits for this test, so a plain Plan G and a Plan G with add-ons are treated as equal. And high-deductible plans can only be exchanged for other high-deductible plans.

Why it matters

Medigap premiums in California are usually attained-age rated, which means your rate goes up as you get older, and different carriers raise rates at different speeds. A plan that was competitively priced when you bought it at 65 may be well above market by 72. The Birthday Rule is your annual chance to fix that without a health review.

What to do

Your carrier is required to notify you no more than 60 days before your birthday. Do not wait for that letter. Call us four to six weeks before your birthday and we will shop your exact plan letter across every carrier we represent, at no cost to you.

Compare my Birthday Rule options: (855) 847-7020 ext. 2

The Birthday Rule is established under California Insurance Code sections 10192.11 and 10192.12. SB 407 (2019) expanded the window from 30 days to 60 days, operative July 1, 2020. The “30 days” figure you may see elsewhere refers to the carrier’s notice deadline, not the window itself.

Medicare Supplement coverage if you are under 65

Federal law does not require insurance companies to sell a Medicare Supplement policy to someone under 65. California law does.

If you qualify for Medicare before 65 because of a disability, California carriers must offer you a Medigap policy. The plans available to you are A, B, D and G, plus K, L, M or N if the carrier sells them.

Two things to know

• Carriers may charge you more. California requires that the coverage be offered but does not cap what a carrier can charge an under-65 enrollee. Rates for beneficiaries under 65 are typically well above the 65-and-over rate, and they vary a lot between companies. Shopping matters more here than anywhere else in the Medigap market.
• End-Stage Renal Disease is excluded. If your Medicare eligibility is based on ESRD rather than another disability, California’s under-65 Medigap requirement does not apply to you. A bill to remove that exclusion, SB 242, did not pass in the 2025-26 session. If you are on Medicare because of ESRD, call us and we will walk you through what is actually available.

When you turn 65 you get a fresh six-month Medigap open enrollment period, with access to every plan letter and standard 65-and-over pricing. Put a reminder in your calendar for the month you turn 65. A lot of people miss it.

California gives you more Medigap rights than federal law does

Guaranteed issue means a carrier must sell you a Medicare Supplement policy without asking health questions. Federal law sets a floor. California goes further in several ways that matter.

Situation	Federal rule	California rule
Open enrollment	6 months from Part B enrollment, at 65 or older	6 months from Part B enrollment, at any age, plus a fresh 6 months after a retroactive Part B eligibility determination
Losing employer coverage	Guaranteed issue only when the employer plan was secondary to Medicare	Guaranteed issue whether the employer plan was primary or secondary
Employer plan changes	Not addressed	Guaranteed issue also applies if your employer plan stops covering the Part B 20% coinsurance, or pays nothing after Medicare
COBRA or Cal-COBRA ending	Limited	Losing COBRA or Cal-COBRA triggers California open enrollment rights
Medi-Cal	Not addressed	Losing Medi-Cal, or being moved to a Share of Cost, triggers guaranteed issue. You can also suspend an existing Medigap policy for up to 24 months while on Medi-Cal
Medical questions during GI	Prohibited from being used	Carriers may not request, require or obtain medical information at all, with one narrow exception for first-time Part B enrollees
Replacing an existing Medigap	Waiting period may apply	No pre-existing condition waiting period

30-day free look. Every Medicare Supplement policy sold in California comes with a 30-day free look. Return it within 30 days of receiving it and you get a full premium refund.

One thing California does not do: it does not require community rating. Carriers here may use attained-age, issue-age or no-age rating, and attained-age is by far the most common. That means most California Medigap premiums increase as you get older, on top of any general rate increase. It is the reason the Birthday Rule exists, and the reason to review your plan every year.

A note on Medi-Cal: it is illegal in California to sell a Medicare Supplement policy to someone with full Medi-Cal benefits. If you have full Medi-Cal, we will tell you so and we will not sell you a policy.

If your Medicare Advantage plan changes on you, you may have a right to a Medigap policy

Most people are told that once you leave your six-month Medigap open enrollment window, you have to answer health questions to get a Medicare Supplement policy. That is usually true. But California law creates a guaranteed issue right that almost nobody knows about: if your Medicare Advantage plan changes in a way that costs you money or takes away a doctor, you can move to a Medigap policy with no medical underwriting.

What counts as a triggering change

Your Medicare Advantage plan does any one of these:

• Reduces any benefit under the plan
• Increases your cost sharing or your premium by any amount
• Drops a provider who is currently treating you, for any reason other than good cause relating to quality of care

The part that trips people up

You may have seen a version of this rule that says the change has to be 15% or more. That figure is real, but it applies to a different step. The law works in two tiers and they have different tests.

Why this matters in practice. If your plan raised a copay 9%, a lot of agents will tell you that you have no rights because it is under 15%. That is wrong. You have a Tier 1 right with your own carrier and its affiliates, with no threshold. The 15% test only decides whether you can escape to an unrelated company.

How long you have

• If you disenroll voluntarily, the window opens 60 days before your disenrollment takes effect and closes 63 days after it.
• If your coverage is terminated involuntarily, the window opens when you receive the termination notice and closes 63 days after coverage ends.
• Your carrier is required to tell you about these rights. If you are disenrolling, that notice is due within 10 working days of the carrier being told.
• You have to submit evidence of the termination or disenrollment date with your application. That is a condition in the statute, not paperwork you can send later.

Which plans you can get

Under the any-carrier route the statute lists Plans A, B, C, F including high deductible F, K, L, M and N. Two things to know about that list. Federal law closed Plans C and F to anyone who first became eligible for Medicare on or after January 1, 2020, and the California text has not been updated since 2012. So if you became eligible on or after that date, the realistic menu is D and G, including high deductible G, plus K, L, M and N. Your own carrier under the Tier 1 route may offer more.

The authority is California Insurance Code section 10192.12(b)(2)(D), for plans regulated by the California Department of Insurance, and the substantively identical Health and Safety Code section 1358.12(b)(2)(D) for Knox-Keene plans regulated by the Department of Managed Health Care, which covers HMOs and most Kaiser and Blue Shield products. The January 1, 2007 amendment is what extended the same-issuer right to a subsidiary of the parent company or a network contracting with the parent. This is general information, not legal advice, and the facts of your plan change matter. If you want a second opinion from someone who is not paid to sell you a policy, HICAP will give you one free at 1-800-434-0222.

Who regulates your coverage, and where to get free help

California is unusual in having two health insurance regulators, and which one covers you depends on what you bought.

• California Department of Insurance (CDI) regulates most Medicare Supplement policies and other health insurance policies sold by insurance companies. Consumer Hotline: 1-800-927-4357.
• Department of Managed Health Care (DMHC) licenses and regulates health care service plans, which means HMOs and most Kaiser and Blue Shield products, including Medigap plans sold under a Blue Cross or Blue Shield trademark. DMHC also runs the Independent Medical Review process for denied care. Help Center: 1-888-466-2219.

The underlying Medigap consumer protections are substantively identical under both agencies. Medicare Advantage and Part D plans are regulated federally by CMS, so an appeal of a Medicare Advantage denial follows the federal appeals process rather than going to CDI or DMHC.

HICAP: free, unbiased Medicare counseling

HICAP is the Health Insurance Counseling and Advocacy Program, California’s federally designated State Health Insurance Assistance Program. It is run by the California Department of Aging, there is an office in every county, and it is completely free. HICAP counselors give one-on-one help with Medicare choices, Part D, Medigap, long-term care insurance and appealing denials. They do not sell anything.

HICAP statewide: 1-800-434-0222

We recommend HICAP without reservation. If you want a second opinion on anything we tell you, call them.

Medicare Supplement Plans in California

Anthem Blue Cross

Anthem Blue Cross offers the most popular Medicare Supplement plans in California with very competitive rates.

Mutual of Omaha

Mutual of Omaha Medicare Supplement Plan usually have the lowest rates. They take an attained-age rating approach to pricing their Medicare supplements and have lower rates for non-tobacco users.

Blue Shield of California

Blue Shield of California offers Medicare Advantage, Part D and Medicare Supplement plans across the state. Separate company from Anthem Blue Cross, with a different network and different rates.

Humana Medicare Supplement

Humana sells Medicare Supplement plans in California. See which plans it offers and how it compares with the other Medigap carriers on this site.

Aetna Medicare Supplement

Aetna Medicare Supplement plans in California are issued by Continental Life and First Health Life & Health. See which plans they offer and how they compare.

Medicare Advantage carriers we represent in California

Medicare Advantage replaces Original Medicare with a private plan. It is a different trade-off from a Medicare Supplement, and which one fits depends on your doctors, your prescriptions and your county.

• Aetna
• Blue Shield of California
• Humana
• UnitedHealthcare
• Wellcare

Plan F eligibility notice. Plan F, high deductible Plan F and Plan C are only available to people who became eligible for Medicare before January 1, 2020. Eligibility is keyed to the date you became eligible for Medicare, not the date your Part A coverage started, which matters if you delayed enrolling. If you became eligible on or after that date, Plan G is the most comprehensive Medicare Supplement plan available to you, and it covers everything Plan F covers except the Part B deductible ($283 in 2026). Compare Plan G or call (855) 847-7020 ext. 2.

Medicare Supplement basics

A Medicare Supplement policy, also called Medigap, pays the share of Part A and Part B costs that Original Medicare leaves to you: coinsurance, copayments and, on some plans, deductibles. Private insurance companies sell them, but the benefits are set by federal law and standardized into lettered plans. Plan G from one company covers exactly what Plan G from another company covers. What differs is the premium, the rate history, and how the company handles claims.

Three things that are specific to buying one in California

No carrier covers the whole state. Which companies will sell to you, and at what rate, depends on your county. The carrier with the lowest Plan G rate in San Diego is often not the lowest in Humboldt or Fresno. Any quote that does not start with your county is a guess.

Almost every California policy is attained-age rated. California does not require community rating. Carriers here may use attained-age, issue-age or no-age rating, and attained-age is by far the most common, which means your premium rises as you get older on top of any general rate increase. Two companies that quote the same rate at 65 can be hundreds of dollars apart by 75. That is the reason the Birthday Rule exists and the reason to review your policy every year.

Your six-month open enrollment window is keyed to Part B, not to your 65th birthday. It starts the month your Part B coverage starts, at any age. If you delayed Part B because you were still working, your window opens then. During it, no carrier can turn you down or charge you more for your health.

Medicare SELECT

Medicare SELECT is a standardized Medigap plan sold at a lower premium in exchange for using a network of hospitals and, in some cases, doctors. The lettered benefits are the same. The restriction is on where you use them. It can be a reasonable trade in a metro area with a strong network and a poor one if you travel or live rurally.

If you want a second opinion on any of this from someone who is not paid to sell you a policy, call HICAP at 1-800-434-0222.

California Medicare Supplement FAQ

What is Medicare Supplement Insurance?

Medicare Supplement Insurance is a private health insurance policy designed to help pay some or all of the costs that are not covered by Medicare Parts A and B.

Who is eligible for Medicare Supplement Insurance?

Anyone who is covered under both Medicare parts A and B is eligible for Medigap Coverage.

When can I apply for Medicare Supplement Insurance?

You can apply for Medicare Supplement Insurance during open enrollment. Open enrollment includes a six-month period from the date you enrolled in Medicare Part B if age 65 or older, or up to six-month after you turn 65 if you were eligible for Part B benefits before age 65. If you become eligible for Medicare Part B benefits before age 65 because of disability or ESRD (permanent kidney failure), you are guaranteed the Medicare Supplement policy of your choice during the first six months you are age 65 and enrolled in Part B.

Does Medicare Supplement coverage include prescription drug benefits?

No, Medicare Supplement is designed to fill in the “gaps” with Medicare Plans such as Part A (which covers hospital and skilled nursing facility care) and Part B (which covers doctor bills and other medical expenses). For prescription drug coverage, you can select a separate Medicare Part D Prescription Drug Plan.

Can I enroll if I do not have Medicare Parts A or B?

No, you must be entitled to Medicare Part A and/or enrolled in Medicare Part B to be eligible for a Medicare prescription drug coverage.

To learn how to get Medicare Part A and/or Part B, please call Medicare at 1-800-MEDICARE (1-800-633-4227), 24 hours a day/7 days a week. For the hearing or speech impaired, please call 1-877-486-2048.

You may also contact your State Medicaid Office or the Social Security Administration at 1-800-772-1213, Monday-Friday, 7 a.m.-7 p.m. CST. For the hearing or speech impaired, please call 1-800-325-0778.

Does Everyone Need a Medicare Supplement Policy?

Not everyone needs a Medicare supplement policy. If you have certain other types of health coverage, the gaps in your Medicare coverage may already be covered. You probably don’t need Medicare supplement insurance if

• you belong to a Medicare Advantage plan
• Medicaid or the Qualified Medicare Beneficiary (QMB) Program pays your Medicare premiums and other out-of-pocket costs.
• You are covered under an employer group health plan

What if I (or my spouse) plan to work after age 65 and continue receiving group health care benefits?

Check with your group plan administrator. You may be able to choose either your group plan or Medicare plus Medicare Supplement coverage. If you stay with your group health care plan, a Special Enrollment Period lets you delay purchasing Part B until you need it.

Will I need to switch doctors if I enroll in a Medicare Supplement plan?

No, you may continue to see your own doctor. Medicare Supplement plans are convenient and flexible, giving you freedom of choice.

Can I see a specialist whenever I want?

Yes. Just remember that your out-of-pocket costs will be less if you choose a physician who accepts Medicare assignment.

What Medicare Doesn’t Cover

Medicare does not cover all health care costs. Medicare coverage consists of Part A (which covers hospital and skilled nursing facility care), and Part B (which covers doctor bills and other medical expenses).

Even with Medicare Part A and Part B coverage, you’re responsible for some out-of-pocket expenses including:

• Part A hospital deductible ($1,736)
• Part B deductible ($283)
• Copayments for hospital stays over 60 days
• Care in a skilled nursing facility after 20 days
• Twenty percent coinsurance for doctor bills and other medical expenses

Eligibility

To qualify for a Medicare Supplement policy, you must be age 65 or older (may vary by state), enrolled in Medicare parts A and B, and you must reside in the state in which you are applying for supplemental coverage.

When to Enroll

Your open enrollment period is the best time to buy a Medicare Supplement policy because companies must sell you any plan they offer regardless of your pre-existing health conditions. Your open enrollment period lasts for 6 months and begins on the first day of the month in which you are age 65 or older and enrolled in Part A and B of Medicare.

Late Enrollment

To help control rising costs, carriers apply the pre-existing condition clause to newly issued Medicare Supplement plans in most states if you enroll after the open enrollment period. Expenses resulting from a condition existing six months prior to the supplemental policy effective date are not covered unless they are incurred three months after the supplemental policy effective date.

If the supplemental policy replaces another creditable individual or group insurance coverage due to a person’s eligibility for Medicare, this Pre-Existing Conditions Limitation will be reduced by the number of months that coverage was in force. If this supplemental policy replaces another Medicare Supplement policy, this Pre-Existing Conditions Limitation will be reduced by the number of months that the coverage was in force.

What each Medicare Supplement plan letter covers

Every Medicare Supplement plan sold today is one of ten standardized letters. The chart below shows what each letter covers. A percentage is the share of the Medicare-approved cost the plan pays. A dash means the plan does not cover it.

Benefit	A	B	C†	D	F†	G	K	L	M	N
Part A coinsurance and hospital costs, up to 365 extra days after Medicare benefits run out	100%	100%	100%	100%	100%	100%	100%	100%	100%	100%
Part B coinsurance or copayment	100%	100%	100%	100%	100%	100%	50%	75%	100%	100%*
Blood, first three pints each year	100%	100%	100%	100%	100%	100%	50%	75%	100%	100%
Part A hospice coinsurance or copayment	100%	100%	100%	100%	100%	100%	50%	75%	100%	100%
Skilled nursing facility coinsurance			100%	100%	100%	100%	50%	75%	100%	100%
Part A deductible		100%	100%	100%	100%	100%	50%	75%	50%	100%
Part B deductible			100%		100%
Part B excess charges					100%	100%
Foreign travel emergency, up to plan limits			80%	80%	80%	80%			80%	80%
Your out-of-pocket limit for 2026							$8,000	$4,000

* Plan N pays the full Part B coinsurance except for a copayment of up to $20 for some office visits and up to $50 for an emergency room visit that does not lead to an inpatient admission.

† Plans C and F are available only to people who became eligible for Medicare before January 1, 2020. Eligibility is keyed to the date you became eligible for Medicare, not the date your Part A coverage started, which matters if you delayed enrolling. If you became eligible on or after that date, Plan G is the most comprehensive plan available to you.

High-deductible Plan F and Plan G pay the same benefits as the standard versions after you have paid a calendar-year deductible of $2,950 in 2026.

Plans K and L pay a percentage of your costs until you reach the annual out-of-pocket limit shown above, then pay 100% of Medicare copayments, coinsurance and deductibles for the rest of the calendar year. That limit does not include Part B excess charges, which you pay yourself. Only Plans F and G cover excess charges.

Plans E, H, I and J were closed to new sales on June 1, 2010. If you already own one it stays in force, but it cannot be purchased today. If you are holding one of these, it is worth having us price a current letter against it.

We do not offer every plan available in your area. Any information we provide is limited to those plans we do offer in your area. Please contact Medicare.gov, 1-800-MEDICARE, or your local State Health Insurance Assistance Program (in California, HICAP at 1-800-434-0222) to get information on all of your options.

California Health Agents is a licensed independent insurance agency, NPN 14924332. We are not affiliated with or endorsed by Covered California, the United States government, the federal Medicare program, the California Department of Insurance, or the Department of Managed Health Care. Plan availability, benefits and premiums vary by county. Quotes are estimates and are not a contract, guarantee of coverage, or offer of insurance.