Medicare Supplement (Medigap) plans in California

A Medicare Supplement policy helps pay some of the costs Original Medicare leaves behind, such as deductibles and coinsurance, and works with any provider that accepts Medicare. In California, standardized plan letters work the same with every company, but prices and underwriting rules differ, and the state's birthday rule gives existing policyholders a yearly chance to review. This guide explains the rules; it does not quote prices.

Your Medigap Open Enrollment Period

Federal rules give you a six-month Medigap Open Enrollment Period that starts the month you are 65 or older and enrolled in Part B. During it, companies cannot deny you or charge more because of health history. Outside it, companies can generally ask health questions unless a guaranteed-issue right or a state rule applies.

How the birthday rule works

California's rule lets current Medigap policyholders switch, during the window starting on their birthday and lasting at least 60 days, to a plan with equal or lesser benefits from any insurer offering it, without medical underwriting. You keep your old policy until the new one starts, so there is no gap.

  • Applies only to people who already have a Medigap policy
  • Equal or lesser benefits only, such as one plan letter to the same or a smaller one
  • Does not apply to Medicare Advantage
  • Confirm current details with the California Department of Insurance

Medigap does not include drug coverage

Medigap policies sold today do not cover outpatient prescriptions, so most people pair one with a standalone Part D plan. Part D plans change formularies and pharmacy networks yearly, so review yours each fall.

Medigap and Medicare Advantage are different

You cannot use a Medigap policy with a Medicare Advantage plan. If you leave Medigap for Medicare Advantage and later want to return, you may face health questions unless a trial right or guaranteed-issue right applies.

Questions to ask before you choose

  • Am I still inside my six-month Medigap Open Enrollment Period?
  • Could the birthday rule move me to a lower-cost policy with equal benefits?
  • Which Part D plan fits my prescriptions alongside a supplement?
  • What happens to my rights if I try Medicare Advantage first?

Frequently asked questions

  • Are Medigap plan letters the same in every company? Yes. Standardized plans with the same letter have the same basic benefits. Price, customer service and rate history differ between companies.
  • Do I need a medical exam for the birthday rule? No. Under the California birthday rule, a company cannot use health questions for a switch to equal or lesser benefits during the window.

Important notice

  • Plan availability and benefits vary by county, plan, and individual circumstances. The Annual Enrollment Period (Oct 15 – Dec 7, 2026) is different from your Initial Enrollment Period around your 65th birthday and from Medigap open enrollment.
  • We do not offer every plan available in your area. Any information we provide is limited to those plans we do offer in your area. Please contact Medicare.gov, 1-800-MEDICARE, or your local State Health Insurance Program (California HICAP) to get information on all of your options. We are not affiliated with or endorsed by the U.S. government or the federal Medicare program.
  • RGI Group is an independent insurance agency based in Austin, Texas; Rolando Gutierrez is licensed in California. We are not Medicare or CMS. Consultations are by phone or video, at no cost and with no obligation. A request is not a confirmed appointment, enrollment, or Medicare permission-to-contact or scope-of-appointment. Do not submit Medicare or Social Security numbers or medical details.

Talk with a licensed Texas agent

Call 346-888-0811. Office: 5900 Balcones Drive, Ste 100, Austin, TX 78731. Monday–Sunday, 8:00 AM–11:00 PM. Licensed in Texas. Guidance available in English and Spanish.