There is a way to discover which is the provider, however. You have to dial the following sequence of numbers: 456 + the mobile number. A recorded voice will tell you the original provider of the number.
Main providers, service numbers and respective prefixes:
| TIM (119) | 330, 331, 333, 334, 335, 336, 337, 338, 339, 360, 363, 366, 368 |
| Vodafone Italia (190) | 340, 342, 345, 346, 347, 348, 349 |
| Wind (155) | 320, 323, 327, 328, 329, 380, 383, 388, 389 |
| 3 Italia (133) | 390, 391, 392, 393 |
Virtual providers
A lot of companies who provide non-telephonic services are trying to join mobile phone companies as virtual operators. These virtual providers utilize the network of the real operators, reselling the service to customers with added incentives or discounts (e.g. discounts on petrol or groceries).
Having a virtual operator means that you get a new mobile phone number because you have purchased this virtual operator's SIM card. You can trace the original provider by the first three numbers of the prefix and the virtual provider by looking at the digit after the hyphen.
Here there is the list of the complete prefixes of virtual operators and their relative supporting providers:
| A-Mobile (Wind) | 389 |
| BT Mobile (Vodafone) | 377-7 |
| CoopVoce (TIM) | 331-1 |
| Daily Telecom Mobile (Vodafone) | 377-8 |
| ERG Mobile (Vodafone) | 377-5 |
| Fastweb (3 Italia) | 373 |
| Italia Mobile | n.d. |
| MTV Mobile (TIM) | 366, 331 |
| Noverca (TIM) | 370-7 |
| PosteMobile (Vodafone): | 377-1 / 377-2 |
| Telepass Mobile (Wind) | n.d. |
| Tiscali Mobile (TIM) | 370-1 |
| UNOMobile (Vodafone) | 377-3 |