| Ottawa Asendorf | Central European Time | -06:00 |
| Ottawa Ayoor | India Standard Time | -10:30 |
| Ottawa Ayer Baloi | Malaysia Time | -13:00 |
| Ottawa Ayer Keroh | Malaysia Time | -13:00 |
| Ottawa Ayer's Cliff | Eastern Time | 00:00 |
| Ottawa Ayia Napa | Eastern European Time | -07:00 |
| Ottawa Ayden | Eastern Time | 00:00 |
| Ottawa Ay | Central European Time | -06:00 |
| Ottawa Axapusco | Central Time | 01:00 |
| Ottawa Avon | Eastern Time | 00:00 |
| Ottawa Avry | Central European Time | -06:00 |
| Ottawa Avsallar Belediyesi | Turkey Time | -08:00 |
| Ottawa Artà | Central European Time | -06:00 |
| Ottawa Arruda dos Vinhos | Western European Time | -05:00 |
| Ottawa America | Central European Time | -06:00 |
| Ottawa Arundel | Eastern Time | 00:00 |
| Ottawa Arvidsjaur | Central European Time | -06:00 |
| Ottawa Asangaon | India Standard Time | -10:30 |
| Ottawa Azalea | Pacific Time | 03:00 |
| Ottawa Azambuja | Western European Time | -05:00 |
| Ottawa Azay-le-Rideau | Central European Time | -06:00 |
| Ottawa Azzano Mella | Central European Time | -06:00 |
| Ottawa Ba | Fiji Time | -18:00 |
| Ottawa Balmain | Eastern Australia Time | -16:00 |
| Ottawa Ballydehob | Ireland Time | -05:00 |
| Ottawa Balsièges | Central European Time | -06:00 |
| Ottawa Bab El Assa | Central European Time | -06:00 |
| Ottawa Ballsbridge | Ireland Time | -05:00 |
| Ottawa Ballston Spa | Eastern Time | 00:00 |
| Ottawa Ballina | Eastern Australia Time | -16:00 |
| Ottawa Ballarat Central | Eastern Australia Time | -16:00 |
| Ottawa Ban Luang | Indochina Time | -12:00 |
| Ottawa Ban Lum | Indochina Time | -12:00 |
| Ottawa Bamber Bridge | United Kingdom Time | -05:00 |
| Ottawa Balwyn | Eastern Australia Time | -16:00 |
| Ottawa Bandar Baru Bangi | Malaysia Time | -13:00 |
| Ottawa Ban Tai | Indochina Time | -12:00 |
| Ottawa Ban Tai | Indochina Time | -12:00 |