| Date | IP Address |
| 2020-10-24 | 52.198.153.219 (ClassC) |
| 2024-01-08 | 52.197.192.28 (ClassC) |
| 2024-04-28 | 57.181.121.207 (ClassC) |
| 2024-06-28 | 18.182.198.195 (ClassC) |
| 2024-07-01 | 52.68.128.62 (ClassC) |
| 2024-10-04 | 52.194.176.193 (ClassC) |
| 2025-04-26 | 35.77.177.78 (ClassC) |
| 2025-09-07 | 54.150.33.78 (ClassC) |
| 2025-09-11 | 13.230.188.111 (ClassC) |
| 2025-10-17 | 52.68.241.23 (ClassC) |
| 2025-11-20 | 18.181.126.192 (ClassC) |
| Date | Domain | IP |
| abc011.contest.atcoder.jp | 2025-09-07 | 54.248.212.207 |
| ijpc2015-2.contest.atcoder.jp | 2023-12-17 | 35.74.49.246 |
| jag2014summer-day2.contest.atcoder.jp | 2023-12-19 | 18.178.198.236 |
| abc013.contest.atcoder.jp | 2025-09-07 | 18.179.245.43 |
| agc013.contest.atcoder.jp | 2024-01-08 | 52.197.192.28 |
| abc043.contest.atcoder.jp | 2023-12-17 | 52.192.87.235 |
| arc004.contest.atcoder.jp | 2024-10-11 | 54.249.159.122 |
| arc075.contest.atcoder.jp | 2023-12-17 | 52.192.87.235 |
| abc026.contest.atcoder.jp | 2025-09-07 | 57.181.78.215 |
| www.abc026.contest.atcoder.jp | 2025-08-27 | 54.95.52.236 |
| abc007.contest.atcoder.jp | 2025-08-27 | 35.74.137.7 |
| arc017.contest.atcoder.jp | 2024-10-11 | 54.249.159.122 |
| abc038.contest.atcoder.jp | 2024-01-07 | 52.198.66.14 |
| tenka1-2016-quala.contest.atcoder.jp | 2024-07-27 | 175.41.250.70 |
| practice.contest.atcoder.jp | 2024-01-09 | 52.193.3.14 |
| code-festival-2014-final-open.contest.atcoder.jp | 2024-01-10 | 52.193.3.14 |