2027 Medicare Advantage exits · CA county detail
Medicare Advantage Plans Leaving San Mateo, CA in 2027
2,191 Medicare Advantage members in San Mateo are in plans that CMS lists as non-renewed for 2027. That is 4.4% of the county’s 49,896 county-level MA members.
Check your plan in San Mateo
Five-digit ZIP only. The lookup runs in your browser.
What is happening in San Mateo
The October 2026 CMS enrollment file shows 49,896 Medicare Advantage members in San Mateo across 35 contract-plan combinations. The CMS 2027 crosswalk marks 7 of those plans as terminated or non-renewed, leaving 2,191 members (4.4%) in plans that end December 31, 2026.
The largest single exit is Alignment Health My Choice (PPO) from Alignment Health Plan, with 1,004 members (2.0% of the county’s MA enrollment). The largest affected organization is Central Health Medicare Plan, with 1,010 affected members.
28 other plans are marked continuing for 2027. Some are “Renewal Plan with SAR” (service area reduced), “Renewal Plan with SAE” (service area expanded), or “Consolidated Renewal Plan” (plan ID or plan structure changes). A continuing plan is not automatically unchanged, so check the plan detail and confirm your doctors and drugs.
Plans ending in San Mateo
The table lists every 2026 plan in the county that the 2027 crosswalk marks as terminated or non-renewed, sorted by 2026 enrollment. The last column shows other 2027 plans in the same county from the plan’s own carrier where available. It is not a recommendation.
| Plan | Carrier | Type | 2026 members | County share | 2027 status | Other 2027 plans in county |
|---|---|---|---|---|---|---|
| Alignment Health My Choice (PPO) | Alignment Health Plan | Local PPO | 1,004 | 2.0% | Exiting in 2027 Exiting (non-renewed for 2027) | Central Health Harmony 031 (HMO) (Alignment Health Plan) Central Health Harmony 031 (HMO) (Alignment Health Plan) |
| Central Health Classic Care Plan IV (HMO) | Central Health Medicare Plan | HMO / HMO-POS | 712 | 1.4% | Exiting in 2027 Exiting (non-renewed for 2027) | Aetna Medicare Signature Extra (HMO) (Aetna Medicare) Central Health Harmony 031 (HMO) (Alignment Health Plan) |
| Central Health Embrace Care Plan (HMO C-SNP) | Central Health Medicare Plan | HMO / HMO-POS Chronic or Disabling Condition | 240 | 0.5% | Exiting in 2027 Exiting (non-renewed for 2027) | Aetna Medicare Signature Extra (HMO) (Aetna Medicare) Central Health Harmony 031 (HMO) (Alignment Health Plan) |
| Aetna Medicare Eagle (PPO) | Aetna Medicare | Local PPO | 95 | 0.2% | Exiting in 2027 Exiting (non-renewed for 2027) | Aetna Medicare Signature Extra (HMO) (Aetna Medicare) Central Health Harmony 031 (HMO) (Alignment Health Plan) |
| Aetna Medicare Enhanced (PPO) | Aetna Medicare | Local PPO | 82 | 0.2% | Exiting in 2027 Exiting (non-renewed for 2027) | Aetna Medicare Signature Extra (HMO) (Aetna Medicare) Central Health Harmony 031 (HMO) (Alignment Health Plan) |
| Central Health Embrace Choice Plan (HMO C-SNP) | Central Health Medicare Plan | HMO / HMO-POS Chronic or Disabling Condition | 42 | 0.1% | Exiting in 2027 Exiting (non-renewed for 2027) | Aetna Medicare Signature Extra (HMO) (Aetna Medicare) Central Health Harmony 031 (HMO) (Alignment Health Plan) |
| Central Health Valor Care Plan (HMO) | Central Health Medicare Plan | HMO / HMO-POS | 16 | 0.0% | Exiting in 2027 Exiting (non-renewed for 2027) | Aetna Medicare Signature Extra (HMO) (Aetna Medicare) Central Health Harmony 031 (HMO) (Alignment Health Plan) |
“Other 2027 plans” means a plan listed as continuing in the same county. It does not confirm that the plan is accepting new members, that your doctors are in network, or that your drugs are covered.
Plans continuing in San Mateo
These plans are listed as continuing for 2027. The table shows the 20 largest by 2026 enrollment; the full list is below. A “Continuing” label does not mean the premium, network, or drug list stayed the same.
| 2026 plan | 2027 plan | Carrier | 2026 members | 2027 status |
|---|---|---|---|---|
| Kaiser Permanente Sr Adv Enhanced Marin San Mateo (HMO) | Same plan name | Kaiser Permanente | 18,994 | Continuing in 2027 Continuing unchanged |
| Kaiser Permanente Senior Advantage Basic San Mateo (HMO) | Same plan name | Kaiser Permanente | 8,016 | Continuing in 2027 Continuing unchanged |
| CareAdvantage (HMO D-SNP) | Same plan name | Health Plan Of San Mateo | 7,947 | Continuing in 2027 Continuing unchanged |
| Alignment Health Sutter Advantage +More (HMO) | Same plan name | Alignment Health Plan | 3,652 | Continuing in 2027 Continuing unchanged |
| Kaiser Permanente Dual Complete North P2 (HMO D-SNP) | Same plan name | Kaiser Permanente | 1,853 | Continuing in 2027 Continuing — service area reduced |
| SCAN Classic (HMO) | Same plan name | SCAN Health Plan | 1,588 | Continuing in 2027 Continuing — plan ID may change |
| Anthem Prime (HMO-POS) | Same plan name | Anthem Blue Cross Partnership Plan | 1,078 | Continuing in 2027 Continuing — service area reduced |
| SCAN Allied (HMO) | Same plan name | SCAN Health Plan | 855 | Continuing in 2027 Continuing unchanged |
| Kaiser Permanente Dual Complete North P22 (HMO D-SNP) | Same plan name | Kaiser Permanente | 543 | Continuing in 2027 Continuing — plan ID may change |
| Anthem Medicare Advantage (HMO-POS) | Same plan name | Anthem Blue Cross | 489 | Continuing in 2027 Continuing unchanged |
| SCAN Balance (HMO C-SNP) | Same plan name | SCAN Health Plan | 480 | Continuing in 2027 Continuing unchanged |
| CCHP Senior Program (HMO) | Same plan name | CCHP (Chinese Community Health Plan) | 426 | Continuing in 2027 Continuing unchanged |
| Aetna Medicare Signature Extra (HMO-POS) | Aetna Medicare Signature Extra (HMO) | Aetna Medicare | 376 | Continuing in 2027 Continuing unchanged |
| SCAN Strive (HMO C-SNP) | Same plan name | SCAN Health Plan | 302 | Continuing in 2027 Continuing — service area expanded |
| Imperial Dynamic Plan (HMO) | Same plan name | Imperial Health Plan of California, Inc. | 251 | Continuing in 2027 Continuing — service area expanded |
| Blue Shield Inspire (HMO) | Same plan name | Blue Shield of California | 245 | Continuing in 2027 Continuing unchanged |
| CCHP Senior Value Program (HMO) | Same plan name | CCHP (Chinese Community Health Plan) | 197 | Continuing in 2027 Continuing unchanged |
| Alignment Health Harmony (HMO) | Central Health Harmony 031 (HMO) | Alignment Health Plan | 99 | Continuing in 2027 Continuing — plan ID may change |
| SCAN MyChoice (HMO) | SCAN Classic (HMO) | SCAN Health Plan | 94 | Continuing in 2027 Continuing — plan ID may change |
| Alignment Health Honor+ Plan (HMO) | Central Health Harmony 031 (HMO) | Alignment Health Plan | 55 | Continuing in 2027 Continuing — plan ID may change |
Show all 28 continuing plans
| 2026 plan | 2027 plan | Carrier | 2026 members | 2027 status |
|---|---|---|---|---|
| Kaiser Permanente Sr Adv Enhanced Marin San Mateo (HMO) | Same plan name | Kaiser Permanente | 18,994 | Continuing in 2027 Continuing unchanged |
| Kaiser Permanente Senior Advantage Basic San Mateo (HMO) | Same plan name | Kaiser Permanente | 8,016 | Continuing in 2027 Continuing unchanged |
| CareAdvantage (HMO D-SNP) | Same plan name | Health Plan Of San Mateo | 7,947 | Continuing in 2027 Continuing unchanged |
| Alignment Health Sutter Advantage +More (HMO) | Same plan name | Alignment Health Plan | 3,652 | Continuing in 2027 Continuing unchanged |
| Kaiser Permanente Dual Complete North P2 (HMO D-SNP) | Same plan name | Kaiser Permanente | 1,853 | Continuing in 2027 Continuing — service area reduced |
| SCAN Classic (HMO) | Same plan name | SCAN Health Plan | 1,588 | Continuing in 2027 Continuing — plan ID may change |
| Anthem Prime (HMO-POS) | Same plan name | Anthem Blue Cross Partnership Plan | 1,078 | Continuing in 2027 Continuing — service area reduced |
| SCAN Allied (HMO) | Same plan name | SCAN Health Plan | 855 | Continuing in 2027 Continuing unchanged |
| Kaiser Permanente Dual Complete North P22 (HMO D-SNP) | Same plan name | Kaiser Permanente | 543 | Continuing in 2027 Continuing — plan ID may change |
| Anthem Medicare Advantage (HMO-POS) | Same plan name | Anthem Blue Cross | 489 | Continuing in 2027 Continuing unchanged |
| SCAN Balance (HMO C-SNP) | Same plan name | SCAN Health Plan | 480 | Continuing in 2027 Continuing unchanged |
| CCHP Senior Program (HMO) | Same plan name | CCHP (Chinese Community Health Plan) | 426 | Continuing in 2027 Continuing unchanged |
| Aetna Medicare Signature Extra (HMO-POS) | Aetna Medicare Signature Extra (HMO) | Aetna Medicare | 376 | Continuing in 2027 Continuing unchanged |
| SCAN Strive (HMO C-SNP) | Same plan name | SCAN Health Plan | 302 | Continuing in 2027 Continuing — service area expanded |
| Imperial Dynamic Plan (HMO) | Same plan name | Imperial Health Plan of California, Inc. | 251 | Continuing in 2027 Continuing — service area expanded |
| Blue Shield Inspire (HMO) | Same plan name | Blue Shield of California | 245 | Continuing in 2027 Continuing unchanged |
| CCHP Senior Value Program (HMO) | Same plan name | CCHP (Chinese Community Health Plan) | 197 | Continuing in 2027 Continuing unchanged |
| Alignment Health Harmony (HMO) | Central Health Harmony 031 (HMO) | Alignment Health Plan | 99 | Continuing in 2027 Continuing — plan ID may change |
| SCAN MyChoice (HMO) | SCAN Classic (HMO) | SCAN Health Plan | 94 | Continuing in 2027 Continuing — plan ID may change |
| Alignment Health Honor+ Plan (HMO) | Central Health Harmony 031 (HMO) | Alignment Health Plan | 55 | Continuing in 2027 Continuing — plan ID may change |
| Kaiser Permanente Senior Advantage Alam., SF, Napa (HMO) | Same plan name | Kaiser Permanente | 46 | Continuing in 2027 Continuing unchanged |
| Kaiser Permanente Sr Adv Enhanced Santa Clara (HMO) | Same plan name | Kaiser Permanente | 29 | Continuing in 2027 Continuing unchanged |
| Imperial Senior Value (HMO C-SNP) | Same plan name | Imperial Health Plan of California, Inc. | 20 | Continuing in 2027 Continuing — service area expanded |
| Kaiser Permanente Sr Adv Enhanced Sac., Sonoma (HMO) | Same plan name | Kaiser Permanente | 19 | Continuing in 2027 Continuing unchanged |
| Anthem Full Dual Advantage Aligned (HMO D-SNP) | Same plan name | Anthem Blue Cross | 15 | Continuing in 2027 Continuing unchanged |
| Kaiser Permanente Sr Adv Enhanced Contra Costa (HMO) | Same plan name | Kaiser Permanente | 14 | Continuing in 2027 Continuing unchanged |
| Kaiser Permanente Senior Advantage Enhanced Solano (HMO) | Same plan name | Kaiser Permanente | 11 | Continuing in 2027 Continuing unchanged |
| DualConnect (HMO D-SNP) | Same plan name | Santa Clara Family Health Plan | 11 | Continuing in 2027 Continuing unchanged |
Your 5-step action plan
- Match the notice to your plan ID Your non-renewal letter should name the contract and plan ID. Compare it with the table above. Non-renewal notices for December 31 contract endings must be sent by October 2, 2026.
- List your doctors, hospital, and drugs Check each 2027 plan’s network and drug list. A lower premium can cost more if your doctors or prescriptions are out of network.
- Compare the 2027 plans in San Mateo Use the continuing-plan table above and Medicare Plan Finder. Confirm the plan is sold in San Mateo for 2027 and is accepting enrollment.
- Enroll by December 7, 2026 Coverage chosen during the Annual Election Period starts January 1, 2027. If you miss it, the non-renewal SEP runs December 8, 2026 through February 28, 2027.
- Check Medigap if you return to Original Medicare The federal guaranteed-issue window is 60 days before the plan ends through 63 days after. For a December 31, 2026 ending, that is November 1, 2026 through March 4, 2027.
If you do nothing
If your Medicare Advantage plan is non-renewed and you do not enroll in a replacement, your coverage ends on December 31, 2026. You return to Original Medicare on January 1, 2027. You may lose dental, vision, hearing, fitness, and other extra benefits that were included in the MA plan.
If your MA plan included Part D, you may also lose drug coverage. You can join a stand-alone Part D plan, but waiting can create a coverage gap and a late-enrollment penalty. If you return to Original Medicare and want a Medigap policy, the guaranteed-issue window is limited; applying after it closes can mean medical underwriting.
2027 deadlines for San Mateo
| Event | Date | What it means |
|---|---|---|
| Annual Election Period (AEP) | October 15 – December 7, 2026 | Join a 2027 Medicare Advantage or Part D plan. A plan chosen here starts January 1, 2027. |
| Non-renewal Special Enrollment Period | December 8, 2026 – February 28, 2027 | For people whose Medicare Advantage plan is leaving. You can switch to another MA plan or return to Original Medicare. |
| 2027 plan year begins | January 1, 2027 | If you do nothing, a non-renewed Medicare Advantage plan ends and you return to Original Medicare. |
| Medicare Advantage Open Enrollment Period | January 1 – March 31, 2027 | If you are already in a Medicare Advantage plan, you can make one change during this window. |
| Medigap guaranteed-issue window | November 1, 2026 – March 4, 2027 | If your MA plan is leaving, you can buy a Medigap policy without medical underwriting during this federal window. |
Medicare resources
- Medicare Plan Finder — compare every plan in your area and enroll.
- 1-800-MEDICARE (1-800-633-4227) — 24 hours a day, 7 days a week.
- California Health Insurance Counseling and Advocacy Program (HICAP) — 1-800-434-0222, free local counseling.
San Mateo Medicare Advantage questions
Is my Medicare Advantage plan leaving San Mateo in 2027?
Use the plan table above or the lookup tool. 7 of the 35 2026 Medicare Advantage plans in San Mateo are marked as terminated or non-renewed for 2027. The other 28 plans are continuing, but some are changing their plan ID or service area.
How many 2027 Medicare Advantage plans are left in San Mateo?
The crosswalk lists 28 distinct 2027 contract-plan targets for San Mateo. This is a derived count: the crosswalk maps plans, not county service areas. Confirm that a specific plan is sold in your county for 2027 with Medicare Plan Finder or the plan itself.
What happens if I do nothing?
If your plan is non-renewed, coverage ends December 31, 2026. On January 1, 2027 you return to Original Medicare. You may lose extra benefits, and a Medicare Advantage plan that included Part D may leave you without drug coverage. You can still use the non-renewal SEP through February 28, 2027 to join another plan.
What is the deadline to change plans?
The Annual Election Period runs October 15 through December 7, 2026. If your plan is leaving, the non-renewal Special Enrollment Period runs December 8, 2026 through February 28, 2027. If you return to Original Medicare and want Medigap, the federal guaranteed-issue window for a December 31 plan ending is November 1, 2026 through March 4, 2027.
Where can I get free help in California?
California Health Insurance Counseling and Advocacy Program (HICAP) provides free, unbiased counseling. Call 1-800-434-0222 or visit the state SHIP page. You can also call 1-800-MEDICARE (1-800-633-4227) or use Medicare Plan Finder.
Does this page include every plan sold in my county?
No. Our plan list comes from the CMS CPSC files and includes Medicare Advantage plans with county-level enrollment. It excludes most employer group plans, PACE plans, and cost plans. If your plan is not listed, call the plan or Medicare.gov to confirm its 2027 status.
Why do you not show the 2027 premium?
The CPSC contract and enrollment files do not include 2027 premiums or drug deductibles. We do not estimate them. Confirm the premium, drug list, and network directly with the plan or Medicare Plan Finder.
Sources and data notes
Data version 2026-11-05; last updated November 5, 2026. Plan status comes from the CMS 2027 Part C&D Plan Crosswalk. Enrollment comes from the October 2026 CPSC county file. Star ratings are 2027 contract-level Part C ratings. Read the methodology and limitations.
- Monthly Enrollment by Contract/Plan/State/County (CPSC), October 2026 — Centers for Medicare & Medicaid Services.
- 2027 Part C&D Plan Crosswalk — Centers for Medicare & Medicaid Services.
- 2027 Star Ratings Data Tables — Centers for Medicare & Medicaid Services.
- MA Plan Directory — Centers for Medicare & Medicaid Services.
- Medicare Advantage in 2026: Enrollment Update and Key Trends — KFF.
- CNN: More than 3 million Medicare Advantage enrollees need to find new plans for 2027 — Better Medicare Alliance.
- Medicare Advantage insurer exits pile up for 2027 — Modern Healthcare.
- CMS Finalizes 2027 Medicare Advantage Rates: 1,471 Counties, 32 Carriers — SeniorWire.
Compiled and checked by the Medicare Plan Exits editorial team against the CMS source files listed above. This page is information only and is not insurance advice or a recommendation of any plan. Medicare Plan Exits is not affiliated with CMS, HHS, or Medicare.gov.