Medicare Advantage in San Mateo County, CA, for 2027.
CMS lists 26 Medicare Advantage plans here for 2027, 7 fewer than 2026 (33). 73,384 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
14 plans with members in the county end or leave it, plus 119 with 10 or fewer members here. CMS moves 2,002 members to another plan, and 45,558 stay in the same plan.
| Plan | Insurer | Members | Why |
|---|---|---|---|
| Alignment Health My Choice (PPO) | Alignment Healthcare USA | 1,004 | Plan terminated |
| Central Health Classic Care Plan IV (HMO) | Molina Healthcare | 712 | Plan terminated |
| Central Health Embrace Care Plan (HMO C-SNP) | Molina Healthcare | 240 | Plan terminated |
| Aetna Medicare Eagle (PPO) | CVS Health | 95 | Plan terminated |
| Aetna Medicare Enhanced (PPO) | CVS Health | 82 | Plan terminated |
| Kaiser Permanente Senior Advantage Alam., SF, Napa (HMO) | Kaiser Foundation Health Plan | 46 | Plan leaves this county |
| Central Health Embrace Choice Plan (HMO C-SNP) | Molina Healthcare | 42 | Plan terminated |
| Kaiser Permanente Sr Adv Enhanced Santa Clara (HMO) | Kaiser Foundation Health Plan | 29 | Plan leaves this county |
| Kaiser Permanente Sr Adv Enhanced Sac., Sonoma (HMO) | Kaiser Foundation Health Plan | 19 | Plan leaves this county |
| Central Health Valor Care Plan (HMO) | Molina Healthcare | 16 | Plan terminated |
Where CMS moves members
| 2026 plan | 2027 plan | Members |
|---|---|---|
| Kaiser Permanente Dual Complete North P2 (HMO D-SNP) | Kaiser Permanente Dual Complete North P22 (HMO D-SNP) | 1,853 |
| SCAN MyChoice (HMO) | SCAN Classic (HMO) | 94 |
| Alignment Health Honor+ Plan (HMO) | Central Health Harmony 031 (HMO) | 55 |
Who holds the members
- Kaiser Foundation Health Plan43,065
- Health Plan of San Mateo7,947
- Alignment Healthcare USA4,839
- UnitedHealth4,311
- California Physicians' Service4,208
- SCAN Group3,319
Individual Medicare Advantage members by parent company, October 2026.
Top rated plans sold here
- Kaiser Permanente Dual Complete North P22 (HMO D-SNP)Kaiser Foundation Health Plan4.5
- Kaiser Permanente Senior Advantage Basic San Mateo (HMO)Kaiser Foundation Health Plan4.5
- Kaiser Permanente Sr Adv Enhanced Marin San Mateo (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 26 plans, open each plan's benefits and star measures, and see what each insurer paid agents in 2026.
Open San Mateo 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.