Medicare Advantage in Contra Costa County, CA, for 2027.
CMS lists 10 Medicare Advantage plans here for 2027, 1 fewer than 2026 (11). 119,720 people in the county had an individual Medicare Advantage plan in October 2026.
Sources: CMS CY2027 plan file (October 2026 release), CMS CY2026 plan file (September 2026 release), CMS enrollment by county (CPSC), October 2026, CMS 2027 Plan Crosswalk (October 1, 2026), CMS 2027 Star Ratings Data Tables (October 8, 2026). Member counts are floors because CMS hides counts of 10 or fewer.
The county in numbers
Plans that end here for 2027
17 plans with members in the county end or leave it, plus 158 with 10 or fewer members here. CMS moves 0 members to another plan, and 74,254 stay in the same plan.
| Plan | Insurer | Members | Why |
|---|---|---|---|
| AARP Medicare Advantage from UHC CA-8 (HMO-POS) | UnitedHealth | 3,394 | Plan terminated |
| Central Health Dual Access Plan (HMO D-SNP) | Molina Healthcare | 157 | Plan terminated |
| Kaiser Permanente Senior Advantage Alam., SF, Napa (HMO) | Kaiser Foundation Health Plan | 123 | Plan leaves this county |
| SCAN Classic (HMO) | SCAN Group | 46 | Plan leaves this county |
| Kaiser Permanente Senior Advantage Basic Alameda (HMO) | Kaiser Foundation Health Plan | 44 | Plan leaves this county |
| Kaiser Permanente Dual Complete North P16 (HMO D-SNP) | Kaiser Foundation Health Plan | 30 | Plan leaves this county |
| Kaiser Permanente Senior Advantage Enhanced Solano (HMO) | Kaiser Foundation Health Plan | 26 | Plan leaves this county |
| Kaiser Permanente Sr Adv Enhanced Sac., Sonoma (HMO) | Kaiser Foundation Health Plan | 23 | Plan leaves this county |
| Kaiser Permanente Sr Adv Enhanced Marin San Mateo (HMO) | Kaiser Foundation Health Plan | 23 | Plan leaves this county |
| Kaiser Permanente Dual Complete North P2 (HMO D-SNP) | Kaiser Foundation Health Plan | 19 | Plan leaves this county |
Who holds the members
- Kaiser Foundation Health Plan92,047
- UnitedHealth10,760
- Humana8,803
- Imperial Health Plan of California2,497
- California Physicians' Service2,288
- Elevance Health1,262
Individual Medicare Advantage members by parent company, October 2026.
Top rated plans sold here
- Kaiser Permanente Dual Complete North P17 (HMO D-SNP)Kaiser Foundation Health Plan4.5
- Kaiser Permanente Sr Adv Basic Contra Costa (HMO)Kaiser Foundation Health Plan4.5
- Kaiser Permanente Sr Adv Enhanced Contra Costa (HMO)Kaiser Foundation Health Plan4.5
2027 overall Star Rating, 4.5 or more. Each plan's measure stars are in the county lookup.
See every plan, premium and copay in the free lookup.
Sort all 10 plans, open each plan's benefits and star measures, and see what each insurer paid agents in 2026.
Open Contra Costa in the lookupWorking this county for AEP?
The AEP 2027 County Kit puts this county and your others in one file: the plans that end, where members land, what is still sold and a crosswalk sheet, with every number tied to its CMS file.
See the AEP 2027 County KitAll California county pages. Facts from public CMS files, prepared by Health and Tech Now. Not plan advice. Check a plan's Summary of Benefits before you enroll.