Use the live implementation sequence, not an undated roadmap.
The calendar matters because the regime did not switch on all at once. Different duties and codes arrived in stages.
Structured answer sets in this page tree.
Cited legal and guidance references.
The UK OSA timeline is operationally important because the assessment and control duties arrived in waves. Teams that do not separate the illegal harms, provider pornography, children access, children risk, and category phases will mis-sequence controls and evidence.
The Act passed on 26 October 2023. Criminal offences introduced by the Act came into effect on 31 January 2024. These early milestones matter because they set the baseline for enforcement culture and service awareness before the main codes landed.
Treat them as the start of the regime, not historical background only.
The illegal harms codes were approved after being laid on 16 December 2024 and Ofcom published illegal risk assessment guidance the same day. Government materials state that illegal risk assessments were due by 16 March 2025 and that Ofcom could enforce from 17 March 2025.
For children, January 2025 brought age assurance guidance for online pornography and the section 81 commencement on 17 January 2025. Child access assessments were due by 16 April 2025. Children risk assessments were due by 24 July 2025 after the child safety codes were laid on 24 April 2025.
Threshold regulations for categories were laid on 16 December 2024. The government expected Ofcom to publish the register of categorised services in summer 2025 and to consult on additional duties from early 2026.
The Statement of Strategic Priorities was designated on 2 July 2025 and should be tracked because it shapes Ofcom focus on safety by design, age assurance, and small but risky services.
Assessment Autopilot can take Deadlines and Compliance Calendar from planning deadlines, owners, and milestones from this page to a reusable workflow inside Sorena. Teams working on Deadlines and can keep owners, evidence, and next steps aligned without copying this guide into separate documents.
Start from Deadlines and Compliance Calendar and turn the guidance into owned tasks, evidence requests, and review checkpoints.
Review your current process, evidence gaps, and next steps for Deadlines and Compliance Calendar.