Key Business Dates for Small Business in the UK September 2025
Important Dates for UK Business Owners in September 2025
September is a pivotal month for business planning balancing the last of summer’s momentum with preparations for a strong final quarter. It brings essential tax, VAT, payroll deadlines, and a rich assortment of marketing opportunities and events. Here’s what you should have on your radar.
Key Accounting & Tax Dates in September 2025
- 1 September 2025 – New Advisory Fuel Rates (AFR) Take Effect
Changes affecting company car users begin on this date. - 19 September 2025 – PAYE, NICs & CIS Payment Deadline (Postal)
For payroll deductions and CIS submissions covering the month ending 5 September 2025. - 22 September 2025 – PAYE, NICs & CIS Payment Deadline (Electronic)
Extended deadline for electronic payments for the same period. - 30 September 2025 – Corporate Accounting Key Dates
- Deadline to file accounts with Companies House for periods ending 31 December 2024.
- Corporation Tax returns due for accounting periods ended 30 September 2024.
- VAT Reminder
If you file quarterly for the period ending 30 September 2025, your VAT return and payment deadline will be 7 November 2025 – but it’s worth noting now to plan ahead.
For more information on Tax, Accounting and Finance Deadlines – Visit the Accounting Wise Blog
Marketing & Sales Dates in September 2025
1 September – Back to School / Zero Waste Week
September marks a major retail opportunity as families gear up for the new school year. Businesses can run targeted promotions on stationery, uniforms, tech, and learning resources.
Zero Waste Week is also a chance to spotlight sustainability – share eco-friendly product ranges, run refill or recycling incentives, and educate customers on reducing waste.
Resource: Zero Waste Week UK
3 September – International Bacon Day
Ideal for cafés, restaurants, butchers, and food brands. Create themed menus, run breakfast promotions, or share bacon-inspired recipes on social media.
4 September – World Sexual Health Day
Raise awareness of sexual health and wellbeing, particularly for health, wellness, and educational businesses. Share trusted resources, host online Q&As, or partner with local clinics.
Resource: Brook – Sexual Health Advice
5 September – International Day of Charity
Encourage “give-back” initiatives – donate a percentage of sales to a chosen cause, promote local fundraising events, or highlight community projects your business supports.
Resource: Charity Commission for England and Wales
8 September – International Literacy Day
A great fit for educational brands, publishers, and training providers. Run book giveaways, create recommended reading lists, or partner with schools to promote reading.
Resource: UNESCO Literacy Day
10 September – World Suicide Prevention Day & National Television Awards
A day to share important mental health resources and show support for wellbeing campaigns, paired with entertainment buzz from the National Television Awards. If relevant, link campaigns to mental health charities or create behind-the-scenes content tied to TV and media.
Resource: Samaritans – Suicide Prevention
15 September – Positive Thinking Day; “100 Days Until Christmas”
Combine motivational messaging with a strategic sales push. Use the “100 days to Christmas” milestone to launch early festive campaigns, pre-order offers, or gift guides.
17 September – National Fitness Day
Highlight promotions on health, fitness, and wellbeing products or services. Gyms can run open days, while sports retailers can offer bundle discounts.
Resource: National Fitness Day UK
21 September – International Day of Peace & World Alzheimer’s Day
Offer empathetic content on peace, unity, and dementia awareness. Support relevant charities, share personal stories, or fundraise.
Resources: Alzheimer’s Society, United Nations International Day of Peace
22 September – Rosh Hashanah & Start of Autumn
Celebrate themes of renewal and reflection for Rosh Hashanah, and introduce autumnal product lines, menus, or promotions as the season officially begins.
23 September – International Day of Sign Languages
Showcase your commitment to accessibility – highlight products or services that support the deaf community, or collaborate with sign language educators.
Resource: British Deaf Association
26 September – Ryder Cup; World Contraception Day
The Ryder Cup is a global golf event, perfect for sports-related marketing and hospitality packages. World Contraception Day provides opportunities for healthcare, education, and public awareness campaigns.
27 September – World Tourism Day
Promote local attractions, travel packages, or “staycation” offers. This is ideal for hospitality, travel agencies, and tourism boards.
Resource: UN World Tourism Day
29 September – World Heart Day
Run campaigns that promote heart health, such as healthy menu options, fitness challenges, or charity partnerships.
Resource: World Heart Federation
30 September – International Podcast Day
Showcase your own podcast content, appear as a guest on other shows, or collaborate with podcast creators in your industry to reach new audiences.
Resource: International Podcast Day
Key Industry Events in September 2025
7–10 September – Trades Union Congress, Brighton
The TUC’s annual conference is the UK’s largest gathering of trade unions, representing millions of workers. This event is a valuable opportunity for HR professionals, employment law specialists, and industries with large workforces to understand the latest developments in workplace rights, pay negotiations, and training initiatives.
Resource: Trades Union Congress
20–23 September – Liberal Democrats Conference, Bournemouth
The party’s annual conference attracts MPs, councillors, activists, and policy experts. Businesses interested in areas such as green energy, civil liberties, or SME support policies can benefit from attending fringe events and networking sessions.
Resource: Liberal Democrats
27 September – 1 October – Labour Party Conference, Liverpool
Labour’s annual conference is one of the largest political gatherings in the UK, with wide media coverage and significant influence on policy direction. It is particularly relevant for businesses affected by potential shifts in taxation, public spending, and regulation.
Resource: Labour Party
19–28 September – Southampton International Boat Show
The UK’s biggest boating and marine industry event, showcasing yachts, powerboats, watersports equipment, and marine services. Ideal for businesses in luxury retail, tourism, outdoor leisure, and manufacturing supply chains. Exhibitors can connect with both trade buyers and high-net-worth consumers.
Resource: Southampton International Boat Show
Bath Children’s Literature Festival (10-day event, typically spanning two weekends in September)
Europe’s largest dedicated children’s literature festival, attracting bestselling authors, illustrators, educators, and families. A fantastic opportunity for publishers, educational businesses, and children’s product retailers to engage with a highly targeted audience. Partnering with or sponsoring events can increase brand visibility and community reach.
Resource: Bath Children’s Literature Festival
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