Medicare Advantage

Jan. 1–Mar. 31: Your Medicare Advantage Switch Window

For 2027, San Francisco is looking at 46 Medicare Advantage plans: 7 new, 12 gone since 2026, and 35 still here but changed on premium, deductible, plan type or name, 13 of them under a new name. Below, how the lineup shifted in San Francisco County and what to compare, with no plan ranked or recommended.

SAN FRANCISCO — The calendar just flipped, and with it opens one of the most misunderstood windows in Medicare. From January 1 through March 31, people already enrolled in a Medicare Advantage plan get a second chance to rethink their choice for the year. Miss these dates, and for most people the next opportunity to make a change won't come until the fall.

Here's how the timing actually works, what you can and can't do during this window, and which deadlines matter most if you live in San Francisco.

What this window is (and isn't)

The Medicare Advantage Open Enrollment Period, or MA OEP, is not the same as the fall Annual Enrollment Period. It's narrower on purpose.

If, on January 1, you are enrolled in a Medicare Advantage plan, you may:

• Switch to a different Medicare Advantage plan, or
• Drop your Medicare Advantage plan and return to Original Medicare (Parts A and B), and add a stand-alone Part D drug plan if you want prescription coverage.

If you are in Original Medicare on January 1, this window is not for you. You cannot use MA OEP to jump from Original Medicare into a Medicare Advantage plan, and you cannot use it to join a stand-alone Part D plan from scratch. Those moves belong to other enrollment periods.

One change, and when it kicks in

MA OEP gives you one election. Once your new plan processes your enrollment, that's your change for the window — you don't get to keep shopping through March.

Coverage under the new choice begins the first day of the month after the plan receives your request. So a change made in January starts February 1; a change made in March starts April 1. Plan ahead if you have surgery, a refill, or a specialist visit scheduled around that switch date.

What happens if you miss March 31

For most people, missing this window means waiting until the fall Annual Enrollment Period — October 15 to December 7 — with coverage changes taking effect January 1 of the following year, according to CMS (medicare.gov).

There are exceptions. Special Enrollment Periods can open outside these windows for specific life events, including:

• Moving to a new address that changes your plan options (a move within or out of San Francisco County can qualify),
• Losing other creditable coverage, such as an employer plan,
• Qualifying for Extra Help or Medicaid,
• Entering, living in, or leaving a nursing facility.

If any of that describes your year, don't assume you have to wait. Call 1-800-MEDICARE or your local State Health Insurance Assistance Program (SHIP) — in California, that's HICAP — to confirm what's open to you.

How MA OEP fits with the other 2027 dates

It helps to see all the deadlines on one calendar:

• January 1 – March 31: Medicare Advantage Open Enrollment Period (one change, current MA members only).
• Anytime: Special Enrollment Periods triggered by qualifying life events.
• October 15 – December 7: Annual Enrollment Period for anyone with Medicare, with changes effective January 1.

A few program-level figures worth knowing while you weigh a change: the Part D out-of-pocket cap is $2,100 in 2026 and $2,400 in 2027, and the maximum Part D deductible is $615 in 2026 and $700 in 2027. The coverage gap (the old "donut hole") is gone as of 2025, replaced by a three-phase drug benefit. There's also the Medicare Prescription Payment Plan, which lets you spread drug costs across the year in monthly installments instead of paying at the pharmacy counter.

Common mistakes to avoid

Assuming you can switch to Medicare Advantage now. You can't — not through MA OEP. That door opens in the fall.

Dropping Medicare Advantage without a Part D plan lined up. If you go back to Original Medicare and want drug coverage, enroll in a stand-alone Part D plan during the same window. Otherwise, you may have a coverage gap and possibly a late enrollment penalty later.

Forgetting to check your doctors. San Francisco is in San Francisco County, where a number of Medicare Advantage plans are offered, and networks vary from plan to plan. Before switching, confirm your primary care provider, specialists, and preferred hospitals are in the new plan's network.

Waiting until March 30. Give yourself time to compare, ask questions, and, if needed, appeal or fix a paperwork issue before the window closes.

Where to get unbiased help

For personalized answers, use the official channels rather than a sales call:

• medicare.gov — the plan finder tool lets you compare Medicare Advantage and Part D options in your ZIP code.
• 1-800-MEDICARE (1-800-633-4227) — available 24/7.
• California HICAP — the state's SHIP program, offering free one-on-one counseling from trained volunteers who don't sell insurance.