| U.S. Virgin Islands | +1340 |
| Uganda | +256 |
| Ukraine | +380 |
| United Arab Emirates | +971 |
| United Kingdom | +649 |
| United Kingdom | +246 |
| United Kingdom | +44 |
| United States | +1 |
| United States | +1 |
| United States | +1808 |
| United States | +1684 |
| United States Minor Outlying Islands | +1 |
| Uruguay | +598 |
| Uzbekistan | +998 |