Newsroom · San Diego County, California

Is Aetna Leaving Medicare Advantage in San Diego for 2027?

Aetna is staying in San Diego County, with a much shorter shelf. Five of the seven plans it sold here this year do not appear anywhere in the CMS 2027 file, and they are the ones most of its local members hold. Here is every plan number, which ones end, which continue, and what the two survivors look like next year.

Medicare On Main Data Desk

Published October 11, 2026 · 8 min read · Reviewed by Brian Penner

The plan number on your card is the answer. I pulled every Aetna row for San Diego County out of the CMS 2026 and 2027 landscape files on October 11 and matched them by contract-plan ID. That is the only reliable way to do it, because plan names repeat and change. Aetna sold two different plans called Signature (HMO) in this county in 2026. One ends. The other continues under a new name. Nothing in this post is a judgment of Aetna. Carriers add and withdraw plans every fall, and our list of the 22 plans ending in San Diego County shows eight organizations doing it this year.

Every Aetna plan in San Diego County, 2026 and 2027

Premium is the monthly plan premium on top of Part B. Cap is the in-network maximum out-of-pocket for the year. The drug deductible is the Part D deductible. Members are San Diego County enrollees in CMS's September 2026 count.

Sources: CMS CY2027 landscape file compared against the CY2026 file by Contract Plan ID; CMS enrollment by contract, plan and county, September 2026. Employer and union group plans are not included. Plan and carrier names are reproduced from the public files for information and do not imply endorsement of any company or plan.

Sources: CMS landscape files · CMS September 2026 enrollment.

Two plans named Signature (HMO), two different outcomes

This is where people will get tripped up. In 2026 Aetna sold Signature (HMO) in San Diego County under two contracts. The benefits the CMS file can show were identical: $0 premium, $2,000 cap, $615 drug deductible.

• H4982-004 had 1,355 county members in September. It is not in the 2027 file.
• H0523-022 had 260. It continues as Signature Legacy (HMO): $10 a month, the same $2,000 cap, a $700 drug deductible.

The file does not tell me whether Aetna is moving any H4982-004 members into another plan, and I will not guess. Your mail does. A letter saying your plan will not be offered next year is a non-renewal notice, and you have to choose. A booklet listing next year's changes is an Annual Notice of Change, and your plan continues. Our post on what a non-renewal letter must say covers how to tell them apart.

If you hold one of the two continuing plans

You are not losing your plan, and you stay enrolled unless you choose something else. Three lines in the Annual Notice of Change deserve a careful read.

• Prime's cap doubles. $1,500 becomes $3,000. The premium stays $0 and the drug deductible goes from $300 to $400. A $3,000 cap is still in the lower half of the county: 15 of the 41 general plans with drug coverage sold here for 2027 have a cap under $3,000.
• Prime's plan type changes. The 2026 file lists it as an HMO-POS and the 2027 file as an HMO. A point-of-service option is what lets some HMO members use certain out-of-network providers. If you ever used that feature, ask the plan what replaces it. The landscape file does not describe it.
• Signature Legacy adds a premium. $0 becomes $10 a month, about $120 over the year, and the drug deductible rises $85. The cap holds at $2,000.

CMS published 2027 Star Ratings on October 8. The contract behind both continuing plans, H0523, is rated 3 stars overall for 2027, the same as the rating shown in the 2026 file (CMS Star Ratings data tables). Ratings belong to the whole contract, not to one plan or county. Every county plan is listed beside its rating in our San Diego Star Ratings post.

If you were in an Aetna PPO

Signature (PPO) was the largest Aetna plan in the county, and with Enhanced (PPO) it held 3,912 members. People pick a PPO for one reason: the right to see doctors outside the network, at a higher cost. If that is why you chose yours, the 2027 shelf is short. These are the county's three general PPO plans with drug coverage, straight from the file.

Source: CMS CY2027 landscape file, San Diego County, general Medicare Advantage plans with drug coverage. This is a list, not a recommendation. The file does not show copays, drug tiers or provider networks.

Three plans is not much choice, and none of them is built like the plan you had. So an Aetna PPO member has a real decision between two things: an HMO with a lower cap and a network you must stay inside, or Original Medicare with a Medigap policy, which has no network at all. That second route is open to you without health questions this winter, and it is the closest thing to a PPO's freedom that exists. More on it below.

Eagle (PPO) members are a separate case. Eagle is a medical-only plan, built for people who get prescriptions elsewhere, often through the VA. It ends, and Aetna's replacement on the shelf is Eagle (HMO), a different plan type with a $4,450 cap. Five medical-only plans are sold in the county for 2027. Moving from the PPO to the HMO is a choice you make, not something to assume happens for you.

If your Aetna plan ended: three doors

Federal rules require a notice by mail at least 90 calendar days before the end date (42 CFR § 422.506). You are not losing Medicare. You are losing one way of receiving it, and you pick the next one. If you pick nothing, you are in Original Medicare on January 1 with no drug plan.

1. Another Medicare Advantage plan sold in San Diego County, chosen between October 15 and December 7 so it starts January 1 (Medicare.gov). There are 41 general plans with drug coverage from 14 organizations. Check your doctors and medical group first, your prescriptions second, the cap third and the premium last.
2. Original Medicare with a Medigap policy and a stand-alone drug plan. Because your plan was discontinued, you can buy Medigap Plan A, B, D, G, K or L with no health questions if you return to Original Medicare, applying from 60 days before to 63 days after your coverage ends (Medicare.gov): November 1, 2026 through March 4, 2027. This is a different right from California's birthday rule (Insurance Code § 10192.11), which helps people who already own a Medigap policy change to another one. How the Medigap window works in California.
3. Original Medicare with a drug plan and no Medigap. The lowest monthly cost and no network, but no yearly limit on your 20% share. Price a hospital stay before you accept it.

Miss December 7 and a Special Enrollment Period still runs from December 8 through February 28 (42 CFR § 422.62), but the start date slides a month at a time, and a gap in drug coverage is the cost of waiting.

The calendar from here

What I would do this week

1. Read the plan number on your card. It starts with H and has a three-digit ending, like H5521-422. Match it to the table above.
2. Sort your mail. Keep the non-renewal letter if you got one. It is your proof for the Medigap door.
3. List every doctor, your medical group, every prescription and your pharmacy. In an HMO county, the medical group decides more than the carrier does.
4. If you were in a PPO, decide what you were using it for. If the answer is a specific out-of-network doctor, check that doctor against Original Medicare before anything else.
5. Be careful with phone calls. A plan ending draws marketing. Nobody can enroll you in a 2027 plan before October 15, and no legitimate agent needs your Medicare number to "verify" anything.

San Diego County has a lot of company this fall. Sharp Health Plan's four individual plans are ending too, and our Sharp Direct Advantage post walks through the same three doors for those members.

How we know all this: the Medicare On Main Data Desk frames every article with public data — here, the CMS CY2026 and CY2027 landscape files compared by Contract Plan ID on October 11, 2026, the CMS September 2026 enrollment file by contract, plan and county, the CMS 2027 Star Ratings data tables published October 8, 2026, and the federal rules and Medicare.gov pages on non-renewal notices, enrollment periods and Medigap guaranteed-issue rights. The landscape file does not show copays, drug tiers, provider networks or whether a carrier moves members from one plan to another. We do not know what any individual member's letter says; your letter and your plan do. Medicare On Main is a licensed independent insurance agency. We do not offer every plan available in your area. Any information we provide is limited to the plans we do offer in your area. Please contact Medicare.gov or 1-800-MEDICARE to get information on all of your options. Not connected with or endorsed by the U.S. government or the federal Medicare program. Mentioning a carrier is not an endorsement or a criticism; plan availability is a fact of the market. This is education, not advice; confirm your plan, costs and eligibility with a licensed agent or Medicare.gov.