California’s SB 346 Has Been Live for 3.5 Months. Which Cities Are Actually Using It to Demand Airbnb Host Data.

Santa Monica filed an $18 million lawsuit against a group of operators who converted more than 25 rent-controlled apartments into illegal Airbnb listings, racking up nearly 3,000 bookings before the city caught them. That lawsuit landed in January 2026, the same month California’s SB 346 went live. And it illustrates the central tension of this story: the cities that already had the tools to catch STR violators are the ones moving fastest under the new law. The cities that needed SB 346 the most? Many of them still have not activated it.

This article provides general information and should not be construed as legal advice. Consult a qualified attorney in your jurisdiction for advice specific to your situation.

If you have been following the SB 346 conversation since we covered the law when it took effect, here is the update you need. The law is real. The enforcement picture is more complicated than the headlines suggest.

What SB 346 Actually Requires (A Quick Refresher)

SB 346, formally the Short-Term Rental Facilitator Act of 2025, was authored by Senator Maria Elena Durazo. It passed the Assembly 64-0, cleared the Senate unanimously, and Governor Newsom signed it on October 13, 2025. The law took effect January 1, 2026, adding Sections 50990 through 50996 to the California Government Code.

The statute gives California cities and counties the authority to require STR platforms (Airbnb, VRBO, Booking.com, and any marketplace that facilitates short-term rental bookings) to hand over specific host data. That data includes:

• Physical address of each short-term rental, including the 9-digit ZIP code
• Assessor parcel number (APN)
• Listing URL from the platform
• Unit-specific information identifying accessory dwelling units, guest houses, or timeshare units at shared addresses

Cities can require this data as often as once per quarter. If local transient occupancy tax (TOT) returns are collected monthly, the city can require platform reports on the same monthly schedule. Platforms must also display applicable local STR license numbers and TOT certificate numbers directly on each listing.

The penalty for non-compliance: administrative fines of up to $10,000 per day. Cities can also audit platform records documenting tax collection, though those audits are conducted at the local agency’s expense.

Here is the critical detail that separates SB 346 from what many hosts expected: the law is not self-executing. A city does not automatically get platform data just because SB 346 exists. Each city or county must adopt its own local ordinance referencing the new Government Code chapter to activate the data-sharing requirements. Until that ordinance passes, the law sits on the shelf.

Which Cities Are Actually Using SB 346 (And Which Are Not)

Three and a half months into the law, the enforcement landscape breaks into three distinct categories: cities that were already doing this before SB 346, cities actively building toward it, and cities that have not moved at all.

Los Angeles: Already Had the Infrastructure

Los Angeles is the closest thing to an SB 346 success story, but calling it a “SB 346 story” undersells what the city was already doing. LA had pre-existing data-sharing agreements with Airbnb and VRBO before SB 346 took effect. The city receives monthly reports from platforms showing physical addresses, nights booked, registration status, and host contact information.

Picture this: you are a host in LA who let your registration lapse six months ago. The city’s automated system cross-references platform data against its registration database. When the mismatch appears (and it will, usually within days), you receive a 10-day compliance warning. After that, daily fines of $2,060 begin accumulating. Then your listing gets pulled from every platform operating in the city.

More than 20,000 properties are currently registered with the city. That number is significantly smaller than the pre-regulation total, and the city credits its platform data pipeline for driving that consolidation. SB 346 strengthens what LA was already doing by codifying it as state law, but LA did not need SB 346 to start demanding data. It was already getting it.

San Francisco: Building the Next Generation

San Francisco’s relationship with short-term rental platforms has been contentious for over a decade (this is the city that Airbnb calls home, which makes every enforcement action feel like an argument at the family dinner table). The city has an existing platform verification system that blocks bookings for unregistered properties, and the Planning Commission recently voted on a significant STR overhaul.

That overhaul included a unified 120-day annual cap across all listing types (approved 4-3), expanded enforcement authority to pursue civil action against platforms without waiting for full administrative proceedings (approved unanimously), and a requirement that the Planning Department notify property owners, residents, HOAs, and neighborhood groups when STR applications are filed (also unanimous).

The commission split on whether to mandate that platforms block unregistered listings outright. Airbnb’s representative pushed back, noting that the company collects and remits more than a million dollars in hotel taxes to the city monthly and cautioning against shifting “regulatory responsibility onto platforms.”

San Francisco has not formally cited SB 346 in its overhaul proceedings based on available public records, but the city is clearly building enforcement tools that align with what SB 346 enables. The planned “SF Host Hub” platform would automate tax collection, occupancy reporting, and neighbor complaint tracking. Whether the city formally adopts a conforming SB 346 ordinance as part of this overhaul remains to be seen.

Santa Monica: Enforcement First, Statute Second

Santa Monica has been one of the most aggressive STR enforcement cities in the country since long before SB 346. The city effectively bans unhosted, entire-home short-term rentals. Only home-sharing (where the host is present) is permitted.

The January 2026 lawsuit mentioned earlier tells you everything about Santa Monica’s approach. The city’s Consumer Protection Unit alleged that Hamid Enayti and associated entities converted more than 25 rent-controlled apartments into illegal Airbnb units, conducting at least 3,000 bookings through 62 separate units. The defendants allegedly communicated outside Airbnb’s platform to have guests sign sham one-year lease agreements, circumventing the city’s Residential Leasing Requirements Ordinance.

The city is seeking disgorgement of approximately $18 million in unlawfully obtained funds, plus civil penalties of $2,500 per violation. That is enforcement with teeth, and it happened without SB 346’s data-sharing mechanism. Santa Monica’s Code Enforcement Division and City Attorney’s office were already equipped to find violators through their own investigative channels.

San Diego: The Gap Between Having Data and Having the Ordinance

San Diego is an interesting case because the city already has a functioning Short-Term Residential Occupancy (STRO) ordinance, adopted in May 2023, that requires platforms to submit monthly listing data. The city’s permit system currently has 964 Tier 3 licenses remaining (Tier 4 is fully closed with zero availability as of February 2026).

But San Diego has not formally adopted a conforming ordinance under SB 346. The city’s existing STRO framework gets much of the same data that SB 346 authorizes, which may explain the lack of urgency. The practical difference for hosts: if San Diego does adopt an SB 346 ordinance, non-compliance penalties jump from whatever the local code prescribes to the state-authorized $10,000 per day for platform non-compliance. That is a different conversation entirely for Airbnb and VRBO’s legal teams.

Palm Springs: STR-Friendly With Its Own Approach

Palm Springs remains one of the most STR-friendly major markets in California. No primary residency requirement. A $100 annual permit fee. Investment properties can list freely. The city does have a dedicated vacation rental compliance department that actively monitors violations, and publicly lists suspended properties, citation numbers, and hotline reports.

Palm Springs modified its STR rules through Ordinance 2118, which removed a planned reduction in the annual contract limit that would have taken effect January 1, 2026. The city has its own enforcement infrastructure, but the question of whether it will layer SB 346 on top of its existing framework is still unanswered. Given Palm Springs’ generally pro-host stance, an aggressive SB 346 adoption would be surprising.

Why Most Cities Have Not Activated SB 346 Yet

The League of California Cities supported SB 346 during the legislative process. But supporting a bill in Sacramento and passing a conforming local ordinance are two very different things. (I have reviewed enough municipal agendas to know that “supported in concept” and “actually implemented” can be separated by years of committee meetings.)

There are several practical reasons most mid-size and smaller California cities have not adopted SB 346 ordinances yet:

They lack existing STR regulatory infrastructure. If your city does not already have an STR permitting system, TOT collection process, or enforcement team, adopting an SB 346 ordinance gives you data you have no staff to process. Knowing that 200 unlicensed STRs operate in your jurisdiction is useful only if you have the personnel to send 200 compliance notices.

The ordinance drafting process takes time. City attorneys need to draft a conforming ordinance. Planning commissions review it. City councils or boards of supervisors vote on it. In smaller cities, this process can take 6 to 12 months from initiation to adoption.

Political will varies. Not every California city wants to crack down on STRs. Tourist-dependent economies (Palm Springs, South Lake Tahoe, Big Bear) may see SB 346 as a tool they do not want to use aggressively. The law gives cities the option. It does not require them to exercise it.

What This Means for California STR Hosts Right Now

Imagine you are a California host with two properties: one in Los Angeles, one in a smaller coastal city. Your LA property already exists in a world where the city receives monthly data from Airbnb showing your address, your registration status, and how many nights you booked. That is your current reality, with or without SB 346.

Your coastal property? The city might not have an STR ordinance at all, let alone one that invokes SB 346. Today, the platform data stays with the platform. But that will not last forever. The question is timing, not direction.

Here is what you should be doing regardless of whether your city has activated SB 346:

Verify your permits are current. If your city has an STR permit system, make sure yours is active and matches what appears on your listing. The most common enforcement trigger under SB 346 is a mismatch between platform data and the city’s registration database.

Confirm your TOT compliance. SB 346 was built around transient occupancy tax enforcement. If you are collecting TOT through the platform (most major platforms remit automatically in California), verify that the amounts match your city’s rates. If you are collecting and remitting yourself, triple-check your numbers.

Display your license number on every listing. Section 50994 requires platforms to display local license numbers and TOT certifications. If your city issues these, make sure they appear on every listing across every platform.

Watch your city council agenda. If your city has not adopted an SB 346 ordinance yet, it may be in the pipeline. Local government transparency websites, city clerk agendas, and planning commission meeting minutes are where you will see this coming before it arrives.

For California STR investors evaluating markets, SB 346 adds a new variable to the analysis. Cities with aggressive enforcement infrastructure (LA, Santa Monica, San Francisco) already operate in a high-compliance environment. That means less competition from illegal operators, which can actually benefit compliant hosts. Markets that have not activated SB 346 may see a wave of enforcement activity once they do. Check any California market on StaySTRA’s California analyzer to see current revenue projections alongside local regulatory conditions.

The Bigger Picture: Platform Data Sharing Is a One-Way Door

SB 346 is part of a larger pattern. Florida’s preemption framework took a different approach by limiting city-level regulation, but the national trend is toward more data transparency between platforms and local governments, not less. New York already requires quarterly platform reports to the city. The EU’s transparency regulation takes effect in May 2026.

For platforms, the calculus is straightforward. Fighting data-sharing requests city by city is expensive and politically damaging. Complying (or at least appearing to comply) is cheaper. Airbnb’s own representative in the San Francisco proceedings noted the company’s significant tax contribution, a sign that the platform is positioning cooperation as its public posture even while pushing back on specific mandates behind closed doors.

For hosts, the trajectory is clear. The era when you could operate an STR without your local government knowing about it is ending. SB 346 accelerates that timeline in California, even if the actual adoption curve is slower than the headlines suggest.

We do our best to keep our regulatory guides accurate and up to date, but ordinances change and we are only human. Always verify current requirements directly with your local municipality before making business decisions.

Run the Numbers on Any California Market

SB 346 changes the compliance picture for California hosts, but the investment fundamentals still depend on the numbers. Use StaySTRA’s analyzer tool to see revenue projections, occupancy data, and competitive analysis for any California market. Or start with our California state page to compare 362 cities side by side.