SIHA runs Junior and Senior weekly competitions in T1 and T4 of each year.
In addition we run the Greater Sydney Cup Association tournaments for age group teams.
For 2025, we have several competitions commening in the first week of Term 4, around 15th October:
| Men's South Competition | Wednesday | Hurstville Aquatic Centre |
| Men's North Competition | Sunday | Mare Bashir Mosman Sports Centre |
| Women's Competition | Wednesday | Ryde Aquatic Centre |
| Mixed Adult Competition | Thursday | Mare Bashir Mosman Sports Centre |
| Schoolgirl's Competition | Wednesday | Multiple Venues |
| Mixed Juniors | Friday | Mare Bashir Mosman Sports Centre |
| Men's Masters | TBC | Narrabeen Academy of Sport |