Quick answer: Medicare Advantage (Part C) plans in San Diego County are offered by private insurance companies and bundle your Part A and Part B coverage, usually with prescription drug coverage included. Plans differ mainly in their provider networks, drug formularies, and out-of-pocket costs — and all three can change every year. The most reliable way to compare is to check each plan against your own doctors, prescriptions, and pharmacy, not against the benefits advertised most heavily. You can review every plan available in your ZIP code at Medicare.gov, get free counseling through California’s HICAP program, or work with an independent licensed broker at no cost to you — brokers are paid by the insurance carriers.

How Medicare Advantage works in San Diego County

Medicare Advantage, also called Part C, is one of the two main ways to receive your Medicare benefits. Instead of using Original Medicare directly, you enroll in a plan offered by a private insurance company that is approved by Medicare. The plan then manages your Part A (hospital) and Part B (medical) coverage, and most plans in San Diego County also include Part D prescription drug coverage in the same package.

Many San Diego plans add extra benefits that Original Medicare does not cover, such as limited dental, vision, or hearing coverage, and some have low or even $0 monthly plan premiums. Two things are worth understanding about those features. First, a $0 plan premium does not mean coverage is free — you still pay your monthly Part B premium, plus the plan’s copays and coinsurance when you use care. Second, extra benefits vary widely in what they actually cover, so it pays to read the details rather than the headline.

The trade-off for these features is that Medicare Advantage plans generally work through provider networks. Which doctors and hospitals are in-network — and how much you pay to go out-of-network, if you can at all — is usually the single biggest practical difference between plans.

Why networks matter so much in San Diego

San Diego County’s care is concentrated in a handful of major health systems: Scripps Health, Sharp HealthCare, UC San Diego Health, Kaiser Permanente, and Palomar Health, along with many independent medical groups. Each Medicare Advantage plan contracts with some combination of these systems and groups — no plan includes every doctor in the county.

That is why the first question to ask about any plan is not “what does it cost?” but “are my doctors in it?” A plan that looks inexpensive on paper can become expensive quickly if your longtime physician, your specialist, or your preferred hospital is outside its network. And because networks are set year by year, a doctor who is in-network this year is not guaranteed to be in-network next year — always check the plan year you are enrolling into, not the current one.

HMO vs. PPO plans

Most Medicare Advantage plans in San Diego County are structured one of two ways:

HMO (Health Maintenance Organization). You choose a primary care physician, generally need referrals to see specialists, and are covered only for in-network care except in emergencies. HMOs often have lower out-of-pocket costs in exchange for the tighter network.

PPO (Preferred Provider Organization). You can see providers outside the network, but you pay more when you do. PPOs offer more flexibility, typically with higher cost-sharing or premiums.

Neither structure is better in the abstract — it depends on whether your doctors are in-network and how much flexibility you want. Some beneficiaries with providers spread across multiple systems find a PPO worth the extra cost; others whose care is centered in one system do well in an HMO.

Five things to check before choosing a plan

  1. Your doctors. Confirm your primary care physician, specialists, and hospital are in the plan’s network for the coming plan year. Verify with the plan’s directory and, ideally, the doctor’s office itself.
  2. Your prescriptions. Each plan has its own formulary (covered drug list) with different tiers and costs. Check every medication you take, including how it is tiered.
  3. Your pharmacy. Plans have preferred pharmacies where your copays are lowest. If you use a specific San Diego pharmacy, confirm how it is treated.
  4. The out-of-pocket maximum. Every Medicare Advantage plan has an annual limit on what you pay in-network for covered medical services. Limits vary by plan — current amounts are listed on each plan’s page at Medicare.gov.
  5. The star rating. Medicare rates plans from 1 to 5 stars each year based on quality and member experience. Ratings are one useful signal among several — a plan’s fit with your doctors and drugs matters more than its rating alone.

Costs beyond the premium — deductibles, copays, coinsurance — are covered in more detail in our guide to what Medicare costs.

When you can enroll or switch

If you are already enrolled in a plan, watch your mail in September for the Annual Notice of Change (ANOC). It lists what your plan is changing for the coming year — premiums, copays, drug coverage, and network — and it is the single most useful document for deciding whether to shop during Annual Enrollment. Our Annual Enrollment Period guide for Southern California covers how the October 15 – December 7 window works step by step.

Medicare Advantage or Medigap?

Medicare Advantage is not the only path. The alternative is staying with Original Medicare and adding a Medicare Supplement (Medigap) policy, which helps pay Original Medicare’s out-of-pocket costs and lets you see any provider in the country that accepts Medicare, plus a standalone Part D drug plan. The two approaches differ in networks, costs, and how underwriting works if you switch later. See our full Medigap vs. Medicare Advantage comparison for a side-by-side look.

Where to get help in San Diego County

You have three good options, and they are free to use:

Frequently asked questions

How many Medicare Advantage plans are available in San Diego County?
The number changes every year and varies by ZIP code. You can see the current list for your address at Medicare.gov or by calling 1-800-MEDICARE.
Are Medicare Advantage plans with a $0 premium really $0?
The plan premium can be $0, but you still pay your monthly Part B premium, plus copays and coinsurance when you receive care. Compare total expected costs, not just the premium.
Can I keep my Scripps or Sharp doctors on any plan?
No plan includes every San Diego provider. Each plan contracts with specific systems and medical groups, and networks change annually — confirm your doctors are in-network for the plan year you are enrolling into.
What happens if I do nothing during Annual Enrollment?
If your plan is continuing next year, you are automatically renewed into it — including any changes described in your Annual Notice of Change. If your plan is not renewing, see our guide on what to do if your Medicare Advantage plan is discontinued.
When can I switch plans if I make the wrong choice?
The Medicare Advantage Open Enrollment Period (January 1 – March 31) allows one switch, and Special Enrollment Periods may apply in certain situations. Otherwise, the next Annual Enrollment Period (October 15 – December 7) is your regular opportunity.
Is a Medicare Advantage HMO or PPO better?
Neither is better for everyone. HMOs generally cost less and require you to stay in-network with referrals; PPOs cost more and allow out-of-network care. The right structure depends on where your doctors are and how much flexibility you want.

Sources & official references

This is a non-government resource and is not affiliated with or endorsed by Medicare.gov or the federal Medicare program. We do not offer every plan available in your area. Please contact Medicare.gov, 1-800-MEDICARE, or your local State Health Insurance Assistance Program (SHIP) — in California, the Health Insurance Counseling and Advocacy Program (HICAP) — to get information on all of your options. Matt Medicares Insurance is an independent insurance brokerage and is not affiliated with or endorsed by Medicare, the Centers for Medicare & Medicaid Services, or any government agency. Educational information only, not individualized advice. Last reviewed: August 2026. Medicare figures and plan details change annually — confirm current amounts and plan availability at Medicare.gov.