ESG reporting deadlines, 2026 to 2029
Every UK and EU sustainability reporting date that matters, who each one applies to, and what you have to have ready. One page, kept current.
What is coming, and when
| Date | Obligation | Who it applies to |
|---|---|---|
| 30 Sept 2026 | Accounts filing for 31 December year ends, carrying SECR in the directors’ report | Large UK companies, roughly 11,900 in scope |
| 15 Dec 2026 | ISSA 5000 applies to assurance engagements for periods beginning on or after this date | Anyone having sustainability information assured |
| 31 Dec 2026 | ESOS Phase 4 qualification date – your status is fixed by this snapshot | UK undertakings with 250+ staff, or turnover above £44m and balance sheet above £38m |
| 1 Jan 2027 | UK CBAM begins | UK importers of aluminium, cement, fertiliser, hydrogen, iron and steel |
| 1 Jan 2027 | UK SRS S2 proposed as mandatory, subject to the FCA policy statement | Around 500 FCA-listed companies. Private companies are not in scope |
| 5 Dec 2027 | ESOS Phase 4 compliance and notification | Everyone who qualified on 31 December 2026 |
| 2028 | CSRD wave 2 first reports, covering FY2027 | Wave 2 companies under the raised Omnibus thresholds |
| 1 Jan 2029 | UK SRS S1 proposed on a comply-or-explain basis | Listed companies, proposed |
2027 is the pinch year. UK SRS S2 starting, ESOS Phase 4 closing and UK CBAM beginning all land in the same twelve months, and the first ISSA 5000 engagements run across it.
Not being in scope does not mean not reporting
Every date above creates a second, larger population: the suppliers of the companies in scope. A listed company preparing UK SRS S2 needs Scope 3 data, and Scope 3 means you. A wave 2 CSRD filer needs value chain data through 2027. An importer facing UK CBAM needs embedded emissions figures from the people who made the goods.
That is why most mid-market companies start sustainability reporting without any filing obligation of their own. The deadline that affects you is usually your customer’s, not yours, and it arrives as a questionnaire with a fortnight’s notice rather than as a statutory date you could plan around.
The practical consequence is that the preparation window is the same either way. If you hold one evidenced dataset, each request draws from it. If you do not, every request restarts the hunt.
What each one actually asks for
SECR
UK energy and carbon disclosure in the directors’ report: UK energy use, associated emissions, an intensity ratio, and the energy efficiency measures taken in the year. Annual, and it follows your accounts filing deadline rather than a fixed date. SECR and UK reporting
ISSA 5000
The assurance standard rather than a reporting standard. It is framework neutral, covers both limited and reasonable assurance, and requires the practitioner to identify and assess risks of material misstatement – at disclosure level for limited assurance, at assertion level for reasonable. In practice it moves the burden onto your evidence and controls. What ISSA 5000 means for your data
ESOS Phase 4
Energy audits across buildings, transport and industrial processes, an action plan, and notification to the Environment Agency. Qualification is fixed on 31 December 2026 and the submission needs twelve months of energy data covering that date. Display Energy Certificates and Green Deal Assessments are no longer accepted routes. ESOS Phase 4 in detail
CSRD and ESRS
The Omnibus raised the thresholds sharply, cutting scope from roughly 50,000 companies to about 5,000, and pushed wave 2 first reports to 2028 for FY2027. The value chain cap limits what an in-scope buyer can demand of a supplier outside scope, which is worth knowing before you answer. CSRD compliance
UK SRS
The UK endorsement of ISSB IFRS S1 and S2, published in final form on 25 February 2026 and voluntary today. The FCA has consulted on making S2 mandatory for listed companies from 1 January 2027, with Scope 3 on comply-or-explain from 2028. TCFD and ISSB disclosure
Questions
When is the ESOS Phase 4 deadline?
The ESOS Phase 4 qualification date is 31 December 2026 and the compliance deadline is 5 December 2027. You must notify the Environment Agency by that date, and your submission has to include twelve months of energy data covering the qualification date.
When does ISSA 5000 take effect?
ISSA 5000 applies to assurance engagements on sustainability information for periods beginning on or after 15 December 2026, or reported as at a date on or after 15 December 2026. Early application is permitted.
When do CSRD wave 2 companies first report?
Under the Omnibus changes, wave 2 first reports are expected in 2028 covering financial year 2027, which makes 2026 and 2027 the preparation window. The thresholds were also raised substantially, taking most mid-market companies out of mandatory scope.
When does UK CBAM start?
The UK Carbon Border Adjustment Mechanism takes effect on 1 January 2027, covering aluminium, cement, fertiliser, hydrogen, iron and steel.
When is SECR due?
SECR is an annual obligation reported in the directors’ report, so it follows your accounts filing deadline. A private company with a 31 December year end files within nine months, so 30 September the following year.
I am not in scope for any of these. Does that mean nothing to do?
Usually not. Companies that are in scope need value chain data from their suppliers, so the questionnaires arrive whether or not you have a filing obligation of your own. That is the most common reason mid-market companies start reporting.
Find out which of these apply to you
Six questions and you get a scope verdict, what your customers can still ask for, and the order to do things in.
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