Key takeaways
- In California, over 7 million people are enrolled in Medicare, with options including Original Medicare (parts A and B), Medicare Advantage (Part C), prescription drug plans (Part D), and Medicare Supplement Insurance (Medigap).
- California residents can choose from various Medicare plans, though specific options vary by location.
- Eligibility for Medicare in California extends to those 65 and older, and younger individuals with certain health conditions or disabilities, with enrollment possible during specific periods or special enrollment periods triggered by life events.
Medicare is a health insurance program designed for individuals ages 65 and older, as well as younger individuals with specific health conditions and disabilities.
It consists of four parts:
- Part A (hospital insurance) and Part B (medical insurance) together form Original Medicare
- Part C, referred to as Medicare Advantage, provides an alternative to Original Medicare
- Part D offers coverage for prescription drugs
If you have Original Medicare, you can also sign up for a supplemental insurance plan (Medigap) to help cover out-of-pocket costs.
2026 Medicare changes
We’re currently updating this article to reflect 2026 costs and other changes.
Read about what’s changing: Open Enrollment for Medicare: Key Changes to Know About Your Plan
According to the Centers for Medicare & Medicaid Services (CMS), 7,050,213 people in California were enrolled in Medicare at the time of the 2025 open enrollment period.
The CMS reported the following trends for the 2026 plan year:
- The average Medicare Advantage monthly premium is set to increase to $13.99 in 2026 from $12.61 in 2025.
- The number of available Medicare Advantage plans is set to decrease to 402 in 2026 from 421 in 2025.
- All Medicare beneficiaries have the option to enroll in a Medicare Advantage plan, with 99.64% having access to plans with $0 premiums.
- All Original Medicare enrollees have the option to buy a stand-alone prescription drug plan.
- There are 12 stand-alone Part D plans available, with $0 being the lowest monthly premium.
- About 32.5% of people with a stand-alone Part D plan receive Extra Help.
Each part of Medicare covers specific services, so it’s important to understand the details of each type.
Original Medicare
Original Medicare is a federal program that includes Part A and Part B. It’s available to anyone who is eligible for Medicare.
- Part A (hosptial insurance): Covers inpatient care and services in hospitals and skilled nursing facilities, as well as hospice care and some home healthcare.
- Part B (medical insurance): Covers outpatient care and services, including doctors’ appointments, speicalists, and preventive care.
Most people qualify for premium-free Part A. However, they are responsible for deductibles and daily coinsurance for each inpatient benefit period. Everyone with Medicare is responsible for paying the Part B monthly premium and annual deductible.
Medicare Advantage
Medicare Advantage (Part C) plans are offered by Medicare-approved private insureranc companies. These plans provide the same coverage as Original Medicare (parts A and B), as well as additional benefits, including:
Many of these plans also include prescription drug coverage (Part D).
Service areas can vary by plan, and each plan sets its own cost and coverage amounts.
Medicare Part D
Medicare Part D plans are provided by Medicare-approved private insurance companies. People with Original Medicare can purchase stand-alone Part D plans from one of these companies.
These plans help cover the costs of both generic and brand-name prescription drugs.
People in California can choose from 12 different prescription drug plans. Service areas can vary by plan. Each plan sets its own cost and coverage amounts.
Medigap
Private insurance companies also partner with Medicare to offer supplemental coverage for Original Medicare beneficiaries, known as Medicare Supplement Insurance (Medigap).
Medigap helps cover certain costs associated with Original Medicare, such as copayments, coinsurance, and deductibles.
People in California can choose from 11 different Medigap plans. Service areas can vary by plan. Each plan sets its own cost and coverage amounts.
You can find Medigap plans available in your area using the Medicare online search tool.
You’re eligible for Medicare if you:
- are age 65 or over
- are a U.S. citizen or legal resident of at least 5 years
If you’re under age 65, you may be eligible for Medicare if you:
- received Social Security Disability Insurance (SSDI) or Railroad Retirement Board (RRB) benefits for at least 24 months
- have end stage renal disease (ESRD) or a kidney transplant
- have amyotrophic lateral sclerosis (ALS)
When can you enroll in Medicare in California?
You can enroll in Medicare or change your coverage during specific periods:
- Initial Enrollment Period (IEP): This lasts for 7 months — 3 months before your 65th birthday, your birth month, and 3 months after.
- Open Enrollment Period (OEP): From October 15 to December 7, you can enroll, switch plans, or drop coverage.
- Medicare Advantage OEP: If you’re already enrolled in a Medicare Advantage plan, you can make changes from January 1 to March 31.
- Medigap OEP: You have six months after turning 65 to enroll in Medigap.
Certain life events can trigger a special enrollment period, allowing you to sign up for Medicare outside of standard enrollment.
Tips for enrolling in Medicare in California
To help you narrow down your options, consider the following:
- Provider network: To maximize your benefits with a Medicare Advantage plan, you may need to use in-network providers. Before enrolling, verify that your healthcare team is included in the network.
- Prescription drugs: Create a complete list of your medications and compare it with the coverage offered by stand-alone prescription drug plans and Medicare Advantage plans in your area. Ensure your medications are covered and reasonably priced.
- Travel coverage: Some Medicare Advantage plans provide coverage outside the plan’s service area. If you travel frequently, it may be beneficial to choose a plan that offers this coverage.
- Plan performance: The CMS publishes annual ratings for Medicare plans, ranging from one to five stars, with five being the best rating.
Medicare has a helpline with staff available 24 hours a day, 7 days a week (excluding some federal holidays) to answer your questions. You can call Medicare at 1-800-633-4227 (TTY: 1-877-486-2048).
For personalized health insurance counseling, contact HICAP, California’sState Health Insurance Assistance Program (SHIP), at 1-800-434-0222.
More than 7 million California residents are enrolled in Medicare.
Dozens of private insurance companies offer Medicare Advantage, Medigap, and stand-alone Part D plans throughout the state.
Overall, monthly premium costs are set to increase for Medicare Advantage plans in California.