Investor Presentation via Investor Meet Company

Costain Group PLC

9 February 2026

Investor Presentation via Investor Meet Company

Full Year 2025 Results Investor Q&A

Costain Group PLC ("Costain") announces that Alex Vaughan, CEO, and Helen Willis, CFO, will be hosting an investor Q&A session relating to the 2025 Full Year Results via Investor Meet Company on 11 March 2026 at 10.00am.

The Q&A session is open to all existing and potential shareholders. Questions can be submitted pre-event via the Investor Meet Company dashboard up until 10:00am the day before the meeting or at any time during the live presentation.

Investors can sign up to Investor Meet Company for free and add to meet Costain via:

https://www.investormeetcompany.com/costain-group-plc/register-investor

Investors who already follow Costain on the Investor Meet Company platform will automatically be invited.

Costain will issue its results for the full year 2025 on 10 March 2026.

Enquiries

Notes to editors

Costain improves people's lives by creating connected, sustainable infrastructure that enables people and the planet to thrive. Through the delivery of predictable, best-in-class solutions across the transport, water, energy and defence markets, we are creating a sustainable future and securing a more prosperous, resilient and decarbonised UK.