Businesses must understand the SB 253 and SB 261 timeline as California’s climate compliance clock ticks, with mandatory emissions and risk reporting starting in 2026.
This timeline breaks down the major deadlines, what’s required, and how to prepare.
At-a-Glance: Key Dates
Date
Requirement
Jan 1, 2025
SB 253 regulations must be adopted
Jan 1, 2026
First SB 253 Scope 1 & 2 disclosures due
Jan 1, 2026
First SB 261 risk report due
2027 (mid-year)
SB 253 Scope 3 disclosures begin (180 days after Scope 1 & 2)
2030
Reasonable assurance required for Scope 1, 2, and Scope 3 emissions
Visual Timeline
SB 253 and SB 261 timeline reporting requirements demand companies with $1B+ in annual revenue doing business in California disclose emissions annually.
SB 253: Emissions Disclosure Timeline
Applies to: Companies with $1B+ in annual revenue doing business in California What’s required: Annual public disclosure of Scope 1, 2, and 3 GHG emissions Standard: Greenhouse Gas Protocol Assurance: Third-party limited (then reasonable) assurance required
Timeline:
Year
Disclosure
Notes
2025
CARB adopts implementing rules
Deadline: Jan 1, 2025
2026
First Scope 1 & 2 reporting
Must follow GHG Protocol
2027
First Scope 3 reporting
Due within 180 days after Scope 1 & 2
2030
Reasonable assurance begins
For Scope 1, 2, and 3 (if required)
SB 261: Climate Risk Disclosure Timeline
Applies to: Companies with $500M+ in revenue doing business in California What’s required: Biennial climate-related financial risk reports Standard: TCFD (or equivalent, e.g. ISSB) Disclosure: Public on company’s website
Timeline:
Year
Disclosure
Notes
2026
First report due
Deadline: Jan 1, 2026
2028
Second report due
Continues every two years
What To Do Now
Here’s your checklist if you’re likely subject to SB 253 or SB 261:
Confirm revenue thresholds ($500M or $1B+)
Assess current GHG data collection capabilities
Identify emission data gaps (especially Scope 3)
Assign internal owners for climate risk reporting
Choose standards (GHG Protocol, TCFD, ISSB)
Set up a timeline tracker aligned to these dates
Prepare for assurance provider engagement (SB 253)
Set up an internal SB 253 and SB 261 timeline tracker to stay ahead of deadlines and prepare for assurance provider engagement. Contact us for a walkthrough or book a demo.
FAQs
What are the key compliance deadlines for SB 253?
CARB must adopt implementing regulations by January 1, 2025; companies must submit their first Scope 1 and 2 emissions disclosures in 2026, Scope 3 disclosures begin in mid‑2027 (within 180 days of the Scope 1 and 2 report), and by 2030 all disclosures require reasonable assurance including Scope 3.
When are companies required to submit their first SB 261 climate risk report?
The first SB 261 risk report is due by January 1, 2026, and subsequent reports are required every two years thereafter.
What assurance requirements apply to SB 253 emissions reporting?
From 2026, Scope 1 and 2 emissions must undergo limited third‑party assurance; by 2030, reasonable assurance is required for Scope 1, 2 and limited assurance begins for Scope 3 disclosures.
Is there enforcement relief during the initial compliance year?
Yes. CARB has stated that it will not enforce penalties in the first reporting year provided companies demonstrate a “good faith effort” to prepare disclosures.
What happens if CARB misses the January 1, 2025 regulation adoption deadline?
CARB missed that statutory deadline and now expects to publish final regulations in 2026 after additional workshops; however, statutory reporting deadlines remain unchanged.
What is the mid‑year 2027 deadline for Scope 3 reporting under SB 253?
Scope 3 emissions must be reported beginning in mid‑2027—specifically within 180 days following the submission of Scope 1 and 2 disclosures made in 2026.
What is the 2030 assurance requirement for SB 253 and SB 261?
By 2030, Scope 1 and 2 emissions reporting must undergo reasonable third‑party assurance, and limited assurance becomes mandatory for Scope 3 emissions; SB 261 does not require formal assurance.
