Medicare enrollment in California

A plain-English guide to when you can sign up, what to choose, and the California rules that matter.

1. Your Initial Enrollment Period

Most people first enroll around age 65. Your Initial Enrollment Period lasts 7 months: the 3 months before the month you turn 65, your birthday month, and the 3 months after. Signing up before your birthday month lets coverage start on time. If you already get Social Security benefits, you are usually enrolled in Parts A and B automatically.

Still working with employer coverage? You may be able to delay Part B without a penalty and use a Special Enrollment Period later. Check with your employer plan before you decide.

2. Choose how you get coverage

• Original Medicare (Parts A and B) plus a separate Part D drug plan, and often a Medigap supplement to cover out-of-pocket costs.
• Medicare Advantage (Part C): an all-in-one plan from a private insurer that usually includes drug coverage and uses a provider network.

3. Yearly dates to remember

• October 15 – December 7: Annual Enrollment — switch Advantage or Part D plans for the next year.
• January 1 – March 31: Medicare Advantage Open Enrollment — change Advantage plans or return to Original Medicare once.
• January 1 – March 31: General Enrollment, if you missed your first chance for Part A or B (late penalties may apply).

4. California Medigap rules

Your best time to buy a Medigap plan is your 6-month Medigap Open Enrollment Period, which starts when you are 65 or older and enrolled in Part B. During it, insurers cannot turn you down for health reasons.

California also has a birthday rule: each year around your birthday you can switch to a Medigap plan with equal or lesser benefits without health questions. Ask us for the current time window and how it applies to your plan.

5. Free help

You can enroll at ssa.gov or by calling Social Security, compare plans at medicare.gov, and get free, unbiased counseling from California's HICAP program (1-800-434-0222).