Medicare Supplement Plans in California 2026: Complete Medigap Guide

Original Medicare is excellent coverage, but it does not pay everything. There is no annual out-of-pocket limit, and costs like the Part B deductible, 20% coinsurance on doctor visits, and hospital copays can add up quickly. Medicare Supplement plans, also called Medigap, exist to fill those gaps. This guide explains how Medigap plans work in California, which plans offer the most value in 2026, and what makes California's rules different from the rest of the country.

What Is a Medicare Supplement Plan?

A Medicare Supplement plan is private insurance that works alongside your Original Medicare (Parts A and B). When you receive care, Medicare pays its share first. Then your Medigap plan covers some or all of the remaining costs, depending on the plan you choose. You keep your own Medicare card and your Medigap card, and you use both when you visit any provider that accepts Medicare nationwide.

Medigap plans are standardized by the federal government. A Plan G from Blue Shield of California covers exactly the same benefits as a Plan G from AARP/UnitedHealthcare. The only differences between carriers are the monthly premium and the quality of customer service.

Medigap Plans Available in California 2026

Ten standardized Medigap plan types are sold in California: A, B, C, D, F, G, K, L, M, and N. Plans C and F are only available to people who became eligible for Medicare before January 1, 2020. For most Californians turning 65 today, the realistic choices are Plan G and Plan N.

Plan G: Most Popular for New Enrollees

Plan G covers nearly everything Original Medicare does not pay, including the Part A hospital deductible ($1,676 in 2026), Part A coinsurance and hospital costs, skilled nursing facility coinsurance, Part B coinsurance (20% of most doctor and outpatient costs), Part B excess charges, and foreign travel emergency coverage up to plan limits. The only cost not covered is the annual Part B deductible ($257 in 2026), which you pay once per year before Plan G begins paying its share.

Plan G is popular because it makes your healthcare costs highly predictable. Once you pay the $257 deductible, you owe nothing for Medicare-covered services for the rest of the year.

Plan N: Lower Premium, Small Copays

Plan N covers the same benefits as Plan G with two differences: you pay a copay of up to $20 for office visits and up to $50 for emergency room visits that do not result in admission. Plan N also does not cover Part B excess charges, which are extra fees some doctors charge above Medicare's approved amount. In California, very few providers charge excess fees, making Plan N a smart cost-saving choice for many people.

High-Deductible Plan G

High-Deductible Plan G has a deductible of $2,870 in 2026 before benefits kick in. Once you meet that deductible, coverage is identical to regular Plan G. The monthly premiums are significantly lower, often under $50 for a 65-year-old. This option suits people who are generally healthy and want a safety net against catastrophic costs without paying high monthly premiums.

Benefit	Plan G	Plan N	HD Plan G
Part A deductible	Covered	Covered	After deductible
Part A coinsurance	Covered	Covered	After deductible
Part B coinsurance	Covered	Covered*	After deductible
Part B excess charges	Covered	Not covered	After deductible
Part B deductible ($257)	You pay	You pay	Counts toward deductible
Skilled nursing coinsurance	Covered	Covered	After deductible
Foreign travel emergency	80%	80%	80% after deductible
Typical monthly premium (age 65)	$120–$220	$90–$160	$30–$55

*Plan N pays Part B coinsurance except for a copay of up to $20 per office visit and $50 per ER visit not resulting in admission. Premiums vary by carrier, age, gender, zip code, and tobacco use.

California's Special Medigap Protections

Open Enrollment Period

Your federal Medigap Open Enrollment Period begins the month you are both 65 or older and enrolled in Medicare Part B. During this 6-month window, insurance companies in California must sell you any Medigap policy they offer, at standard rates, regardless of your health history. Missing this window means underwriting applies, and you could be denied or charged higher premiums based on your medical conditions.

California's Birthday Rule

California has a law that most other states do not: the Birthday Rule. Every year, within 60 days of your birthday, you may switch to a Medigap plan with equal or lesser benefits from any carrier, without medical underwriting. This is a powerful protection because it lets you shop for lower premiums every year without risking denial due to a new diagnosis. For example, if you have Plan G with Company A and Company B offers the same plan at a lower rate, you can switch during your birthday window.

Guaranteed Issue Rights

Beyond the Birthday Rule, California offers guaranteed issue rights in specific situations. If you lose employer coverage, if your Medicare Advantage plan leaves your area, or if you move out of your plan's service area, you have the right to enroll in certain Medigap plans without medical underwriting.

Medigap vs. Medicare Advantage: Which Is Right for You?

This is the most important decision new Medicare enrollees face. Both approaches are legitimate, but they serve different needs.

Medigap works best if you travel frequently, have doctors you want to keep who accept Medicare nationwide, want predictable costs with no network restrictions, or have ongoing health conditions that require regular specialist care. Medicare Advantage may make more sense if you want extra benefits like dental, vision, hearing, and fitness included in one plan, you prefer lower monthly premiums and are comfortable with a network, or you qualify for a plan with a $0 premium.

One critical difference: if you have Medigap and later want to switch to Medicare Advantage and then back to Medigap, you may face underwriting and be denied. The decision to start with Medigap is often easier to maintain than to reverse. Speak with a licensed California Medicare agent before making this choice.

How to Choose and Enroll in a Medigap Plan in California

Since benefits are standardized, the right plan comes down to three questions: Which plan type fits your health needs and budget? Which carrier offers the lowest premium for that plan in your zip code? Is the carrier financially stable and highly rated for customer service?

Do not buy the first plan you see. Premium differences for the exact same Plan G can range by $50 to $100 per month between carriers in the same California zip code. Over a year that is $600 to $1,200 in avoidable costs.

For Spanish-speaking Californians exploring Medicare Supplement options, our sister site BeneficiosMedicare.com offers step-by-step guides in Spanish on Medicare coverage choices.

Frequently Asked Questions

What is the best Medicare Supplement plan in California for 2026?

Plan G is the most comprehensive option for new Medicare enrollees. It covers nearly all out-of-pocket costs except the Part B deductible ($257 in 2026). Plan N offers lower premiums with small copays and is a strong choice if you rarely visit the emergency room.

Can I be denied a Medigap plan in California?

Not during your Open Enrollment Period, which runs for 6 months starting the month you are both 65 and enrolled in Part B. Outside this window, carriers can use medical underwriting. California's Birthday Rule gives you an annual chance to switch plans without underwriting.

How much does Medigap Plan G cost in California?

A 65-year-old non-smoker in California can typically expect Plan G premiums between $120 and $220 per month in 2026, depending on the carrier, zip code, and gender. Premiums rise with age, so enrolling early locks in the lowest starting rate.

What is the difference between Medigap and Medicare Advantage?

Medigap works alongside Original Medicare and lets you use any provider that accepts Medicare anywhere in the country. Medicare Advantage replaces Original Medicare with a private plan that uses networks and often includes extra benefits. Medigap usually has higher monthly premiums but lower and more predictable total costs.