Medicare Advantage in California: 2027 Coverage, Explained

158 Medicare Advantage plans in California are changing for 2027, 74 plans are leaving and 66 plans are new. Use this guide to see how the plans work in California and what to compare, in plain terms.

One fact shapes every Medicare decision in California: your county, not your state, sets your options. Neighboring counties can look surprisingly different, which is exactly why the guides here are local.

About 52% across California have chosen Medicare Advantage over Original Medicare, though that share swings a lot depending on where you live.

Ahead: the companies active statewide, how Original Medicare, Advantage, Medigap and Part D fit together, the shared 2027 costs, enrollment windows, free unbiased help, and a guide for every California city.

How your Medicare choices fit together

Almost everyone starts with Original Medicare — Part A (hospital) and Part B (medical), run by the federal government. From there, you generally choose one of two directions, and understanding the fork is the whole game.

The Medicare Advantage path (Part C). You get your Part A and Part B benefits through a private plan approved by Medicare, usually with drug coverage included. Plans work within networks and service areas set at the county level, which is why availability in California depends on your county, not just your state.

The Original Medicare path. You stay with the government program and can add a stand-alone Part D drug plan, and often a Medigap policy to help with the out-of-pocket costs Original Medicare leaves behind — trading bundled extras for broad provider freedom.

Neither path is universally better; the right fit depends on your doctors, your prescriptions, your budget, and how you like to handle care. This guide explains how each works in California so you can decide for yourself. We don't rank or recommend specific plans.

The 2027 numbers, from shared to plan-specific

Start with what's fixed for everyone. The standard Part B premium is $202.90 per month in 2026 (2026 amount; 2027 figure will be posted when CMS releases it), and Part A is premium-free for most people who paid Medicare taxes long enough while working.

On the drug side, Part D has real guardrails for 2027: a deductible capped at $700 and, a hard $2,400 ceiling on your out-of-pocket costs for covered prescriptions — the old coverage gap is gone.

Higher earners pay more for Parts B and D through an income-related adjustment called IRMAA, which for 2026 starts above $109,000 in annual income for an individual and is based on your 2024 tax return. Most people fall below that line and pay the standard amounts. The 2027 brackets will be posted when CMS releases them.

Everything past that is plan-specific: the premiums, copays, and coverage details of an individual Advantage or Medigap plan change from plan to plan and year to year. Rather than quote or rank those, we point you to Medicare's Plan Finder and a licensed agent for your exact numbers.

When you can enroll or make changes

Medicare's enrollment windows are federal — the same nationwide — so the timing below applies wherever you live.

Your first window (IEP). When you're new to Medicare, your Initial Enrollment Period is the 7-month window around your 65th birthday month. Signing up on time helps you avoid late penalties that can follow you for years.

Annual Enrollment Period (AEP, also called Open Enrollment). Each fall, from October 15 – December 7, anyone with Medicare can join, switch, or drop a Medicare Advantage or Part D plan. Changes take effect January 1.

Medicare Advantage Open Enrollment. From January 1 – March 31, if you're already in an Advantage plan you get one chance to switch plans or return to Original Medicare.

Special Enrollment Periods can also open after certain life events, like moving or losing other coverage. The interactive calendar further down lays the year out visually.

Getting unbiased help in California

You never have to make these decisions alone, and you don't have to pay for good help. A few free, trustworthy starting points:

Medicare.gov and 1-800-MEDICARE (TTY 1-877-486-2048) are the official sources for plan details and the Plan Finder. Licensed agents can also compare options with you and handle enrollment.

And to be clear about who we are: MyMedicarePlans.org is a privately owned, independent educational resource. We are not Medicare, not a government agency, and not affiliated with one. We publish plain-language information to help you get oriented — then point you to the official sources and licensed professionals for decisions about specific plans.

California cities

Pick your city for the county-level picture, the companies active in your area, and local guides: