| School | Roll number | County | Total (latest year) | Latest average class size | Largest class | Classes 30+ |
|---|---|---|---|---|---|---|
| Castlebar Primary School | 20562H | Mayo | 864 | 25.03 | 28 | 0 |
| BREAFFY N S | 13781F | Mayo | 377 | 22.81 | 28 | 0 |
| ST PETERS NS | 19916J | Mayo | 271 | 22.58 | 31 | 3 |
| GAELSCOIL RAIFTEIRÍ | 19832D | Mayo | 229 | 25.44 | 32 | 2 |
| BALLYVARY CENTRAL N S | 19402B | Mayo | 223 | 26.62 | 31 | 2 |
| BALLINTUBBER N S | 07374G | Mayo | 113 | 27.00 | 32 | 1 |
| Castlebar Educate Together National School | 20457K | Mayo | 113 | 22.60 | 27 | 0 |
| ST JOSEPHS N S | 13152U | Mayo | 111 | 21.00 | 31 | 1 |
| SN Beal Atha na hEin | 13444K | Mayo | 95 | 23.75 | 28 | 0 |
| St Paul's National School | 17562N | Mayo | 89 | 22.25 | 25 | 0 |
| S N B CURNANOOL | 14497N | Mayo | 66 | 22.00 | 23 | 0 |
| S N an Teaghlaigh | 18562S | Mayo | 45 | 15.00 | 16 | 0 |
| S N NAOMH BRID C | 18503C | Mayo | 21 | 10.50 | 15 | 0 |
| S N AN COILL MHOR | 17321O | Mayo | 17 | 8.50 | 9 | 0 |
| CRIMLIN N S | 15967G | Mayo | 15 | 7.50 | 8 | 0 |