Medicare Advantage vs Medigap in California: How to Choose

Medicare Advantage vs Medigap is really a choice between two ways to get your Medicare. With Original Medicare plus a Medigap policy, you can see any doctor or hospital in the US that accepts Medicare, and the policy helps pay costs Original Medicare leaves to you. With a Medicare Advantage plan, you get your Part A and Part B coverage through a private company that contracts with Medicare, usually with drug coverage included.

Neither path fits everyone. The right fit depends on your doctors, your prescriptions, how you like to pay for care and, in California, the timing rules for buying a Medigap policy.

Two ways to get your Medicare coverage

Original Medicare with a Medigap policy

Original Medicare is Part A (hospital insurance) and Part B (medical insurance). A Medigap policy, also called Medicare Supplement Insurance, works alongside it. Depending on the plan you choose, it helps pay some or all of the deductibles and coinsurance you would otherwise owe.

Medigap doesn’t include drug coverage, so on this path you add a stand-alone Medicare drug plan (Part D) if you want it. You then pay three premiums: Part B, Medigap and the drug plan.

Medigap Plans C and F are only for people who were first eligible for Medicare before January 1, 2020.

Medicare Advantage (Part C)

Medicare Advantage plans are offered by private companies that contract with Medicare. They usually include drug coverage. Many also include some dental, vision and hearing benefits, which Original Medicare generally doesn’t cover for routine care. These extras vary by plan, so check the plan’s Evidence of Coverage.

Many plans are HMOs or PPOs. HMO plans generally require you to use in-network doctors and hospitals and often need referrals to see specialists. PPO plans let you go out of network, at a higher cost. Each plan has a yearly out-of-pocket maximum for covered Part A and Part B services.

You still pay your Part B premium in a Medicare Advantage plan. For 2026, CMS set the standard Part B premium at $202.90 a month.

Medicare Advantage vs Medigap: side by side

	Original Medicare + Medigap	Medicare Advantage
Cost structure	Part B premium, plus premiums for the Medigap policy and a drug plan. The policy helps pay deductibles and coinsurance, depending on the plan.	Part B premium, plus any plan premium. You pay copays or coinsurance as you use care, up to the plan’s yearly out-of-pocket maximum.
Doctor choice	Any doctor or hospital in the US that accepts Medicare.	HMOs generally require in-network providers and often referrals. PPOs allow out-of-network care at a higher cost.
Drug coverage	Not included. Add a stand-alone Part D plan.	Usually included.
Travel in the US	Same rule everywhere: any provider that accepts Medicare.	Depends on the plan’s network and rules. Ask how the plan covers care away from home.
Extra benefits	Routine dental, vision and hearing generally aren’t covered. You can buy stand-alone dental or vision insurance.	Many plans include some dental, vision and hearing benefits. They vary by plan.
When you can buy or switch	Medigap open enrollment (6 months), California’s yearly birthday window, or other times when medical questions may apply.	Your Initial Enrollment Period, Annual Enrollment (October 15 – December 7), the Medicare Advantage Open Enrollment Period (January 1 – March 31) and Special Enrollment Periods.

The table is a general guide. Costs and benefits differ from plan to plan, so compare the actual plans offered where you live.

When you can buy or switch in California

Your Medigap open enrollment period

Your Medigap open enrollment period lasts 6 months. It starts the month you’re 65 and enrolled in Part B. During this window, you can buy a Medigap policy without answering medical questions.

If you delay Part B because you have coverage from a current job, this window doesn’t start until you sign up for Part B. Our article on Medicare and employer coverage explains that timing. New to Medicare? Start with our Turning 65 checklist.

The Medigap California birthday rule

California gives people who already have a Medigap policy an extra right each year. During an annual window of at least 60 days beginning on your birthday, you can switch to another Medigap plan with equal or lesser benefits without answering medical questions.

The California Department of Insurance explains the exact dates and rules. This right is for switching from one Medigap policy to another. It doesn’t help you move from a Medicare Advantage plan into Medigap.

Leaving Medicare Advantage later

You can leave a Medicare Advantage plan and return to Original Medicare during Annual Enrollment or the Medicare Advantage Open Enrollment Period. If you return to Original Medicare between January 1 and March 31, you may also join a stand-alone drug plan. Our guide to the Medicare Advantage Open Enrollment Period covers the details.

The catch is Medigap. Outside your protected windows, a Medigap insurer may ask medical questions. Depending on your health, you might not be able to buy the policy you want, or it may cost more. Some situations may give you a right to buy a policy without medical questions. The California Department of Insurance or HICAP can tell you whether one applies to you.

This is the part of the Medicare Advantage vs Medigap choice that’s hardest to undo. If you’re turning 65 and leaning toward Medicare Advantage, think about whether you might want Medigap later.

Medicare Advantage pros and cons: which is right for me?

1. Which doctors and hospitals do you want to keep? Check whether they accept Medicare and, for a Medicare Advantage plan, whether they’re in the network.
2. What prescriptions do you take? Compare each plan’s drug list, whether it’s a Medicare Advantage plan or a stand-alone Part D plan.
3. How do you like to pay for care? Medigap means a monthly premium that helps cover deductibles and coinsurance. Medicare Advantage means copays as you use care, up to a yearly limit.
4. Do you travel or spend part of the year away from home? A plan’s network rules may matter more if you’re away often.
5. How much do dental, vision and hearing matter to you? See what Medicare covers for dental, vision and hearing.
6. What if your health changes? Remember that buying Medigap later may involve medical questions.

For one-on-one counseling at no charge, you can call HICAP, California’s Health Insurance Counseling & Advocacy Program (1-800-434-0222). You can also call Medicare at 1-800-MEDICARE (TTY 1-877-486-2048) or visit Medicare.gov.

Frequently asked questions

Can I have Medicare Advantage and a Medigap policy at the same time?

No. A Medigap policy works only with Original Medicare, and it won’t pay costs in a Medicare Advantage plan. If you’re thinking about leaving a Medigap policy to join a Medicare Advantage plan, consider whether you could buy a Medigap policy again later.

What is California’s birthday rule for Medigap?

If you already have a Medigap policy in California, you get an annual window of at least 60 days beginning on your birthday. During it, you can switch to another Medigap plan with equal or lesser benefits without answering medical questions. The California Department of Insurance has the exact dates.

Medicare Supplement vs Medicare Advantage: which costs less?

There’s no single answer; it depends on your care, your prescriptions and the plans available. With Medigap, you pay the Part B, Medigap and drug plan premiums, and the policy helps with deductibles and coinsurance. With Medicare Advantage, you pay the Part B premium plus any plan premium, then copays up to the plan’s yearly maximum. Compare your likely total costs for a year, not just the premiums.

Can I switch from Medicare Advantage to Medigap later?

You can return to Original Medicare during Annual Enrollment or the Medicare Advantage Open Enrollment Period. Buying a Medigap policy at that point may mean answering medical questions, unless you have a protected right to buy one. Ask the California Department of Insurance or HICAP before you make the change.

Talk with a licensed Boomers agent

A licensed Boomers agent can go over the Medicare plans we represent in your area and check them against your doctors and prescriptions.

Find a licensed agent near you · See upcoming Medicare events

Or call 1-800-815-1943 (TTY 711), Monday – Friday, 9 AM – 5 PM Pacific.

Sources

• Compare Original Medicare and Medicare Advantage (Medicare.gov)
• Medigap (Medicare Supplement Insurance) (Medicare.gov)
• Choosing a Medigap Policy guide (Medicare.gov)
• Medicare Advantage and other health plans (Medicare.gov)
• 2026 Medicare Parts A & B premiums and deductibles (CMS.gov)
• Medicare Supplement Insurance “Medigap” (California Department of Insurance)
• Medicare Counseling (HICAP) (California Department of Aging)