Medicare is health insurance coverage for people age 65 and over. You may also be eligible for Medicare if you’re under 65 years old and are living with certain disabilities or health conditions.

Medicare plans in California include:

  • original Medicare: a federal health insurance program administered by the Centers for Medicare & Medicaid Services (CMS)
  • Medicare Advantage: plans offered through private insurance companies who contract with CMS
  • Medicare prescription drug plans: insurance plans that cover prescription drug costs

Part A (inpatient and hospital coverage)

Part A covers care you receive while staying in hospitals, critical access hospitals, and a limited time in skilled nursing facilities. Most people don’t pay a monthly premium for Part A plans, but there is a deductible if you’re admitted into a hospital.

Part B (outpatient and medical coverage)

Part B covers care outside of a hospital for things such as:

  • doctors’ visits
  • diagnostic screenings
  • lab tests
  • durable medical equipment

You will pay an additional premium for Part B plans. Premiums are set by CMS and change each year based on overall healthcare costs.

Part D (prescription drug coverage)

Everyone on Medicare is eligible for (Part D), but you must get it through a private insurer. It’s important to compare these plans because costs and coverage vary.

Medicare Advantage

Medicare Advantage plans (Part C) are offered through private insurers who bundle all your coverage for parts A and B, and sometimes prescription drug coverage, into a single plan. With Medicare Advantage plans, you still pay the Medicare Part B premium.

Medicare Advantage plans must cover the same things as Medicare parts A and B, but some have extra coverage (and an additional premium) for things like:

In California, Medicare Advantage plans fall into three categories: Health Maintenance Organizations (HMOs), Preferred Provider Organizations (PPOs), and Special Needs Plans (SNPs).


With an HMO, you choose a primary care physician who coordinates your care and refers you to specialists as needed. Most plans require you to get care from providers in the HMO network.

Care outside of the HMO network usually is not covered unless it’s emergency care, out-of-area urgent care, or out-of-area dialysis.

Some HMO plans require you to purchase separate prescription drug coverage (Part D).

The availability of HMO plans in California varies by county, and they are not available everywhere.


With a PPO, you can get care from networks of doctors and facilities that provide services covered under your plan.

You can also get care from a medical provider outside of your network, but your out-of-pocket expenses will usually be higher.

Most PPOs don’t require a referral to see a specialist.

California does not have any statewide Medicare Advantage PPO plans, but 21 counties have local PPO plans available.


SNPs are available to people who need a higher level of coordinated care and care management. You may be able to get an SNP if you:

  • have a chronic or disabling health condition, such as diabetes or chronic heart failure
  • are “dual eligible” for both Medicare and Medicaid
  • live in a nursing home or similar institution or live at home but get the same level of care as someone in a nursing home

Providers in California

These companies offer Medicare Advantage plans in California:

  • Aetna Medicare
  • Alignment Health Plan
  • Anthem Blue Cross
  • Blue Cross of California
  • Brand New Day
  • Central Health Medicare Plan
  • Clever Care Health Plan
  • Golden State
  • Health Net Community Solutions, Inc.
  • Health Net of California
  • Humana
  • Imperial Health Plan of California, Inc.
  • Kaiser Permanente
  • Scan Health Plan
  • UnitedHealthcare
  • WellCare

Not every carrier offers plans throughout the state, so the choices you have available will vary depending on your county of residence.

California residents are eligible for Medicare and Medicare Advantage plans if:

  • you’re a citizen of the United States or legal resident for the past 5 or more years
  • you are ages 65 or over, and you or a spouse meets the requirements for work in a Medicare-sponsored job

People under age 65 may be eligible if:

If you still have questions about whether you qualify, you can use Medicare’s online eligibility tool.

Initial coverage enrollment period

The initial coverage enrollment period (EIP) is a 7-month period that starts three months before your 65th birthday and ends 3 months after you turn 65 years old. If you enroll, your coverage will begin the first of the month that you turn 65 years old.

If you delay enrollment until the month of or after your birthday, you may have a gap in your health insurance.

Annual election period

You can enroll in Medicare Advantage plans between October 15 and December 7 each year. Coverage begins January 1.

Medicare Advantage open enrollment

If you’re already on a Medicare Advantage plan and want to switch to another Medicare Advantage plan or go to original Medicare, you can do that between January 1 and March 31 each year.

General enrollment period

The general enrollment is between January 1 and March 31 each year. If you have Medicare Part A and want to enroll in Part B, a Medicare Advantage plan, or Part D coverage you can do it during this time. Coverage is effective July 1.

Special enrollment periods

Special enrollment periods allow you to enroll outside the normal enrollment periods under special circumstances. For example, the special enrollment period allows you to enroll in a new plan with no penalty if you lose an employer-sponsored insurance plan and need to enroll in Part B, or move out of your current plan’s service area.

Medicare and Medicare Advantage plans in California can be confusing, so before you sign up it’s important to evaluate your choices and compare factors like:

  • costs
  • coverage
  • providers and facilities in the plan’s network
  • CMS star ratings for Part C and Part D plans

If you need help determining which plans are best for your needs or you have questions about available options, there are plenty of resources to assist you.

Health Insurance Counseling & Advocacy Program (HICAP)

The California Department of Aging offers Medicare counseling through HICAP. They provide:

  • information on Medicare enrollment
  • explanations of Parts A, B, and C, and how to determine what coverage you need
  • answers to questions about Part D prescription drug coverage, costs, and eligibility

HICAP is confidential and free for anyone eligible for Medicare or about to become eligible. You can search for local HICAP services by county or call 800-434-0222.


Contact Medicare directly for assistance with enrollment or plan questions by calling 800-MEDICARE (800-633-4227) or visit You can also call the regional CMS office in San Francisco at 415-744-3501.

Employer-sponsored coverage

If you have concerns or need help with Medicare California coverage purchased through an employer, contact the California Department of Managed Health Care at 888-466-2219 or email

When you’re ready to sign up for Medicare in California:

  • determine what coverage you need and research available plans, coverage options, and costs
  • contact HICAP or Medicare if you have questions about eligibility or coverage
  • find out when the next enrollment period begins

This article was updated on October 5, 2020 to reflect 2021 Medicare information.


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