L3 — 12 codes dans 12 localités (Canada).
| Code postal | Localité / Quartier | Zone administrative | Coordonnées |
|---|---|---|---|
| Welland East | Welland · Ontario | 42.9878, -79.2219 | |
| Welland West | Welland · Ontario | 42.9998, -79.2656 | |
| Port Colborne | Ontario | 42.9001, -79.2329 | |
| Grimsby | Ontario | 43.2001, -79.5663 | |
| Markham Central | Markham · Ontario | 43.8769, -79.2686 | |
| Markham Outer Southwest | Markham · Ontario | 43.8479, -79.3288 | |
| Markham Southeast | Markham · Ontario | 43.8486, -79.2617 | |
| Thornhill East | Ontario | 43.8227, -79.3946 | |
| Orillia | Ontario | 44.6087, -79.4207 | |
| Newmarket Southwest | Newmarket · Ontario | 44.0433, -79.4912 | |
| Newmarket Northeast | Newmarket · Ontario | 44.0565, -79.4555 | |
| Bradford | Ontario | 44.1168, -79.5663 |