| 20/06/25 | 07:00:04 | 20 Jun 2025 | | Transaction in Own Shares | RNS |
| 19/06/25 | 15:37:28 | 19 Jun 2025 | | Holding(s) in Company | RNS |
| 16/06/25 | 07:00:08 | 16 Jun 2025 | | £10m Share Buyback Programme & H1 Trading Update | RNS |
| 09/06/25 | 15:38:40 | 9 Jun 2025 | | Holding(s) in Company | RNS |
| 09/06/25 | 07:00:03 | 9 Jun 2025 | | Heathrow Site Visit | RNS |
| 04/06/25 | 12:17:20 | 4 Jun 2025 | | Costain awarded Anglian Water contract extension | RNS |
| 04/06/25 | 11:50:33 | 4 Jun 2025 | | Holding(s) in Company | RNS |
| 02/06/25 | 16:37:07 | 2 Jun 2025 | | Total Voting Rights | RNS |
| 02/06/25 | 15:45:43 | 2 Jun 2025 | | Holding(s) in Company | RNS |
| 29/05/25 | 12:19:48 | 29 May 2025 | | Holding(s) in Company | RNS |
| 28/05/25 | 07:00:03 | 28 May 2025 | | Refinancing of Bank and Bonding Facilities | RNS |
| 27/05/25 | 15:49:01 | 27 May 2025 | | Additional Listing | RNS |
| 22/05/25 | 13:19:22 | 22 May 2025 | | Holding(s) in Company | RNS |
| 19/05/25 | 15:16:27 | 19 May 2025 | | Holding(s) in Company | RNS |
| 19/05/25 | 11:32:04 | 19 May 2025 | | Holding(s) in Company | RNS |
| 15/05/25 | 16:40:35 | 15 May 2025 | | Result of AGM | RNS |
| 15/05/25 | 07:00:07 | 15 May 2025 | | AGM Trading Update | RNS |
| 07/05/25 | 17:16:37 | 7 May 2025 | | Holding(s) in Company | RNS |
| 06/05/25 | 18:05:11 | 6 May 2025 | | Holding(s) in Company | RNS |
| 01/05/25 | 14:35:11 | 1 May 2025 | | Total Voting Rights | RNS |
| 28/04/25 | 12:32:35 | 28 Apr 2025 | | Scrip Dividend Reference Price | RNS |
| 25/04/25 | 09:28:36 | 25 Apr 2025 | | Holding(s) in Company | RNS |
| 22/04/25 | 14:40:21 | 22 Apr 2025 | | Holding(s) in Company | RNS |
| 09/04/25 | 14:48:26 | 9 Apr 2025 | | Director/PDMR Shareholding | RNS |
| 08/04/25 | 10:47:18 | 8 Apr 2025 | | Annual Financial Report | RNS |
| 02/04/25 | 09:19:34 | 2 Apr 2025 | | Additional Listing | RNS |
| 01/04/25 | 13:34:29 | 1 Apr 2025 | | Holding(s) in Company | RNS |
| 20/03/25 | 07:00:04 | 20 Mar 2025 | | Costain awarded Urenco framework agreement | RNS |
| 11/03/25 | 07:00:08 | 11 Mar 2025 | | Costain FY 2024 | RNS |
| 10/02/25 | 12:00:01 | 10 Feb 2025 | | Investor Presentation via Investor Meet Company | RNS |
| 27/01/25 | 07:00:06 | 27 Jan 2025 | | Trading Update with Strong Forward Work Position | RNS |
| 02/01/25 | 11:13:49 | 2 Jan 2025 | | Block listing Interim Review | RNS |
| 24/12/24 | 10:19:28 | 24 Dec 2024 | | Steve Mogford External Appointment | RNS |
| 19/12/24 | 07:00:07 | 19 Dec 2024 | | Siemens and Costain JV wins HS2 Systems Contract | RNS |
| 12/12/24 | 14:22:48 | 12 Dec 2024 | | Holding(s) in Company | RNS |
| 11/12/24 | 07:00:05 | 11 Dec 2024 | | Costain / East Coast Cluster | RNS |
| 04/12/24 | 07:00:06 | 4 Dec 2024 | | Costain Wins New HS2 Systems Contract | RNS |
| 02/12/24 | 13:39:14 | 2 Dec 2024 | | Total Voting Rights | RNS |
| 14/11/24 | 07:00:04 | 14 Nov 2024 | | Transaction in Own Shares | RNS |
| 13/11/24 | 07:00:05 | 13 Nov 2024 | | Transaction in Own Shares | RNS |
| 12/11/24 | 07:00:05 | 12 Nov 2024 | | Transaction in Own Shares | RNS |
| 11/11/24 | 07:00:06 | 11 Nov 2024 | | Transaction in Own Shares | RNS |
| 08/11/24 | 07:00:04 | 8 Nov 2024 | | Transaction in Own Shares | RNS |
| 07/11/24 | 07:00:06 | 7 Nov 2024 | | Transaction in Own Shares | RNS |
| 06/11/24 | 07:00:04 | 6 Nov 2024 | | Transaction in Own Shares | RNS |
| 05/11/24 | 07:00:06 | 5 Nov 2024 | | Transaction in Own Shares | RNS |
| 04/11/24 | 07:00:03 | 4 Nov 2024 | | Transaction in Own Shares | RNS |
| 01/11/24 | 09:41:27 | 1 Nov 2024 | | Total Voting Rights | RNS |
| 01/11/24 | 07:00:03 | 1 Nov 2024 | | Transaction in Own Shares | RNS |
| 31/10/24 | 07:00:06 | 31 Oct 2024 | | Transaction in Own Shares | RNS |
