| 26/08/26 | 10:00:01 | 26 Aug 2026 | | Transaction in Own Shares | RNS |
| 20/08/26 | 13:02:38 | 20 Aug 2026 | | Holding(s) in Company | RNS |
| 19/08/26 | 11:55:52 | 19 Aug 2026 | | Transaction in Own Shares | RNS |
| 13/08/26 | 07:00:02 | 13 Aug 2026 | | Half-year Financial Results | RNS |
| 12/08/26 | 10:00:01 | 12 Aug 2026 | | Transaction in Own Shares | RNS |
| 05/08/26 | 10:32:39 | 5 Aug 2026 | | Transaction in Own Shares | RNS |
| 03/08/26 | 10:00:00 | 3 Aug 2026 | | Total Voting Rights | RNS |
| 29/07/26 | 10:30:00 | 29 Jul 2026 | | Transaction in Own Shares | RNS |
| 27/07/26 | 07:00:09 | 27 Jul 2026 | | Investor Presentation via Investor Meet Company | RNS |
| 22/07/26 | 13:57:10 | 22 Jul 2026 | | Transaction in Own Shares | RNS |
| 15/07/26 | 10:30:01 | 15 Jul 2026 | | Transaction in Own Shares | RNS |
| 15/07/26 | 07:00:03 | 15 Jul 2026 | | Costain extends contract with United Utilities | RNS |
| 09/07/26 | 11:15:13 | 9 Jul 2026 | | Transaction in Own Shares | RNS |
| 01/07/26 | 10:30:01 | 1 Jul 2026 | | Transaction in Own Shares | RNS |
| 01/07/26 | 09:30:13 | 1 Jul 2026 | | Block Listing Interim Review | RNS |
| 01/07/26 | 09:25:10 | 1 Jul 2026 | | Total Voting Rights | RNS |
| 25/06/26 | 10:25:14 | 25 Jun 2026 | | Director/PDMR Shareholding | RNS |
| 24/06/26 | 10:30:00 | 24 Jun 2026 | | Transaction in Own Shares | RNS |
| 23/06/26 | 10:11:59 | 23 Jun 2026 | | Director/PDMR Shareholding | RNS |
| 18/06/26 | 11:46:28 | 18 Jun 2026 | | Director/PDMR Shareholding | RNS |
| 18/06/26 | 07:00:07 | 18 Jun 2026 | | Costain wins West Winch Housing Road contract | RNS |
| 17/06/26 | 10:30:00 | 17 Jun 2026 | | Transaction in Own Shares | RNS |
| 10/06/26 | 09:27:04 | 10 Jun 2026 | | Transaction in Own Shares | RNS |
| 09/06/26 | 15:25:11 | 9 Jun 2026 | | Holding(s) in Company | RNS |
| 09/06/26 | 07:00:03 | 9 Jun 2026 | | Costain wins place on £700m TfL framework | RNS |
| 03/06/26 | 10:30:00 | 3 Jun 2026 | | Transaction in Own Shares | RNS |
| 01/06/26 | 10:31:24 | 1 Jun 2026 | | Total Voting Rights | RNS |
| 27/05/26 | 09:34:23 | 27 May 2026 | | Transaction in Own Shares | RNS |
| 22/05/26 | 13:00:00 | 22 May 2026 | | Director/PDMR Shareholding | RNS |
| 20/05/26 | 09:55:24 | 20 May 2026 | | Transaction in Own Shares | RNS |
| 18/05/26 | 13:51:26 | 18 May 2026 | | Additional Listing | RNS |
| 18/05/26 | 09:39:37 | 18 May 2026 | | Director Declaration | RNS |
| 14/05/26 | 16:28:17 | 14 May 2026 | | Result of AGM | RNS |
| 14/05/26 | 07:00:04 | 14 May 2026 | | AGM Trading Update | RNS |
| 13/05/26 | 17:14:43 | 13 May 2026 | | Holding(s) in Company | RNS |
| 13/05/26 | 10:19:56 | 13 May 2026 | | Transaction in Own Shares | RNS |
| 12/05/26 | 16:01:28 | 12 May 2026 | | Holding(s) in Company | RNS |
| 06/05/26 | 09:35:46 | 6 May 2026 | | Transaction in Own Shares | RNS |
| 05/05/26 | 14:08:44 | 5 May 2026 | | Director/PDMR Shareholding | RNS |
| 01/05/26 | 16:08:57 | 1 May 2026 | | Scrip Dividend Reference Price - Replacement | RNS |
| 01/05/26 | 09:08:11 | 1 May 2026 | | Total Voting Rights | RNS |
| 30/04/26 | 15:17:34 | 30 Apr 2026 | | Director/PDMR Shareholding | RNS |
| 29/04/26 | 10:14:56 | 29 Apr 2026 | | Transaction in Own Shares | RNS |
| 27/04/26 | 12:27:08 | 27 Apr 2026 | | Scrip Dividend Reference Price | RNS |
| 22/04/26 | 17:06:08 | 22 Apr 2026 | | Director/PDMR Shareholding | RNS |
| 22/04/26 | 11:48:55 | 22 Apr 2026 | | Transaction in Own Shares | RNS |
| 21/04/26 | 17:15:56 | 21 Apr 2026 | | Holding(s) in Company | RNS |
| 16/04/26 | 16:59:20 | 16 Apr 2026 | | Holding(s) in Company | RNS |
| 15/04/26 | 15:16:31 | 15 Apr 2026 | | Transaction in Own Shares | RNS |
| 15/04/26 | 15:05:12 | 15 Apr 2026 | | Director/PDMR Shareholding | RNS |
