Phone numbers in Ontario, California
Ontario has 132 phone prefixes in area codes 840, 909.
Biggest holders: AT&T Mobility, Verizon Wireless, Frontier. This is the local calling area (rate center) where those prefixes were first assigned.
- Mobile carrier 52%
- Local phone company 18%
- Internet / business phone carrier 22%
- Paging service 4%
- Phone company 4%
Every prefix in Ontario
Search the first six digits of a number in this list. If it's here, the number started in Ontario with the carrier shown. If it isn't, check the California page or look the number up.
| Prefix | Carrier | Type | Assigned |
|---|---|---|---|
| 840-237 | Onvoy | Internet / business phone carrier | 2023 |
| 840-269 | Onvoy | Internet / business phone carrier | 2025 |
| 840-270 | AT&T Mobility | Mobile carrier | 2025 |
| 840-279 | Verizon Wireless | Mobile carrier | 2025 |
| 840-295 | AT&T Mobility | Mobile carrier | 2026 |
| 840-400 | Fractel | Internet / business phone carrier | 2021 |
| 840-699 | Fractel | Internet / business phone carrier | 2021 |
| 840-840 | Onvoy | Internet / business phone carrier | 2025 |
| 909-208 | MetroPCS (T-Mobile) | Mobile carrier | – |
| 909-210 | AT&T Mobility | Mobile carrier | – |
| 909-212 | Tpx Communications | Internet / business phone carrier | 2007 |
| 909-214 | AT&T Mobility | Mobile carrier | 2001 |
| 909-215 | AT&T Mobility | Mobile carrier | 2001 |
| 909-218 | Charter / Spectrum | Internet / business phone carrier | 2007 |
| 909-223 | AT&T Mobility | Mobile carrier | 2001 |
| 909-224 | AT&T Mobility | Mobile carrier | 2001 |
| 909-225 | AT&T Mobility | Mobile carrier | 2001 |
| 909-226 | AT&T Mobility | Mobile carrier | 2001 |
| 909-227 | AT&T Mobility | Mobile carrier | 2001 |
| 909-228 | AT&T Mobility | Mobile carrier | 2001 |
| 909-229 | Verizon Wireless | Mobile carrier | – |
| 909-230 | Tpx Communications | Internet / business phone carrier | – |
| 909-234 | AT&T Mobility | Mobile carrier | 2001 |
| 909-235 | MetroPCS (T-Mobile) | Mobile carrier | 2007 |
| 909-238 | Verizon Wireless | Mobile carrier | – |
| 909-239 | Verizon Wireless | Mobile carrier | – |
| 909-240 | Verizon Wireless | Mobile carrier | – |
| 909-241 | Verizon Wireless | Mobile carrier | – |
| 909-249 | Spok | Paging service | – |
| 909-259 | Peerless Network Of California | Internet / business phone carrier | 2009 |
| 909-260 | Verizon Wireless | Mobile carrier | – |
| 909-261 | Verizon Wireless | Mobile carrier | – |
| 909-262 | AT&T Mobility | Mobile carrier | – |
| 909-268 | T-Mobile (including Sprint) | Mobile carrier | – |
| 909-284 | MetroPCS (T-Mobile) | Mobile carrier | 2010 |
| 909-286 | AT&T Mobility | Mobile carrier | 2001 |
| 909-292 | Tpx Communications | Internet / business phone carrier | – |
| 909-295 | MetroPCS (T-Mobile) | Mobile carrier | 2011 |
| 909-309 | Spok | Paging service | – |
| 909-319 | T-Mobile (including Sprint) | Mobile carrier | 2002 |
| 909-321 | CenturyLink / Lumen | Local phone company | – |
| 909-322 | MetroPCS (T-Mobile) | Mobile carrier | – |
| 909-331 | MCImetro (Verizon Business) | Internet / business phone carrier | – |
| 909-354 | Verizon Wireless | Mobile carrier | 2005 |
| 909-376 | T-Mobile (including Sprint) | Mobile carrier | – |
| 909-390 | Frontier | Local phone company | – |
| 909-391 | Frontier | Local phone company | – |
| 909-395 | Frontier | Local phone company | – |
| 909-400 | Utility Telecom Group | Phone company | – |
| 909-405 | Spok | Paging service | – |
| 909-408 | MetroPCS (T-Mobile) | Mobile carrier | 2017 |
| 909-418 | AT&T (local phone) | Local phone company | – |
| 909-437 | T-Mobile (including Sprint) | Mobile carrier | – |
| 909-443 | Onvoy | Internet / business phone carrier | – |
| 909-456 | Level 3 (Lumen) | Internet / business phone carrier | – |
| 909-457 | Utility Telecom Group | Phone company | – |
| 909-458 | Frontier | Local phone company | – |
| 909-459 | Frontier | Local phone company | – |
| 909-460 | Frontier | Local phone company | – |
| 909-467 | Frontier | Local phone company | – |
| 909-472 | Teleport Communications America | Internet / business phone carrier | – |
| 909-489 | T-Mobile (including Sprint) | Mobile carrier | – |
| 909-490 | T-Mobile (including Sprint) | Mobile carrier | 2016 |
| 909-509 | AT&T Mobility | Mobile carrier | 2006 |
| 909-510 | Windstream (PAETEC) | Internet / business phone carrier | – |
| 909-518 | Verizon Wireless | Mobile carrier | – |
| 909-519 | Verizon Wireless | Mobile carrier | – |
| 909-544 | Verizon Wireless | Mobile carrier | 2006 |
| 909-545 | MetroPCS (T-Mobile) | Mobile carrier | 2009 |
| 909-563 | Matrix Telecom, Llc. S/i/i Tnci | Internet / business phone carrier | – |
| 909-564 | American Messaging Services | Paging service | – |
| 909-604 | American Messaging Services | Paging service | – |
| 909-605 | Frontier | Local phone company | – |
| 909-615 | AT&T Mobility | Mobile carrier | 2001 |
| 909-635 | Tpx Communications | Internet / business phone carrier | – |
| 909-638 | Verizon Wireless | Mobile carrier | – |
| 909-657 | Level 3 (Lumen) | Internet / business phone carrier | – |
| 909-661 | North County Communication | Phone company | – |
| 909-669 | Shelcomm | Phone company | – |
| 909-673 | Frontier | Local phone company | – |
| 909-678 | MetroPCS (T-Mobile) | Mobile carrier | 2014 |
| 909-687 | T-Mobile (including Sprint) | Mobile carrier | 2015 |
| 909-702 | AT&T Mobility | Mobile carrier | – |
| 909-704 | MetroPCS (T-Mobile) | Mobile carrier | 2018 |
| 909-717 | MetroPCS (T-Mobile) | Mobile carrier | – |
| 909-721 | T-Mobile (including Sprint) | Mobile carrier | – |
| 909-724 | Level 3 (Lumen) | Internet / business phone carrier | – |
| 909-730 | Verizon Wireless | Mobile carrier | – |
| 909-731 | Verizon Wireless | Mobile carrier | – |
| 909-732 | Verizon Wireless | Mobile carrier | – |
| 909-738 | MetroPCS (T-Mobile) | Mobile carrier | 2017 |
| 909-740 | Matrix Telecom, Llc. S/i/i Tnci | Internet / business phone carrier | – |
| 909-750 | Tpx Communications | Internet / business phone carrier | 2016 |
| 909-757 | Onvoy | Internet / business phone carrier | 2016 |
| 909-772 | T-Mobile (including Sprint) | Mobile carrier | – |
| 909-773 | Frontier | Local phone company | – |
| 909-778 | AT&T Mobility | Mobile carrier | 2019 |
| 909-781 | Verizon Wireless | Mobile carrier | 2006 |
| 909-786 | Level 3 (Lumen) | Internet / business phone carrier | 2005 |
| 909-789 | AT&T Mobility | Mobile carrier | 2017 |
| 909-813 | AT&T Mobility | Mobile carrier | 2019 |
| 909-815 | Verizon Wireless | Mobile carrier | – |
| 909-816 | Verizon Wireless | Mobile carrier | – |
| 909-821 | MetroPCS (T-Mobile) | Mobile carrier | 2001 |
| 909-842 | 33 Wireless | Mobile carrier | – |
| 909-843 | Matrix Telecom, Llc. S/i/i Tnci | Internet / business phone carrier | – |
| 909-850 | Skyetel | Internet / business phone carrier | – |
| 909-851 | AT&T Mobility | Mobile carrier | – |
| 909-906 | Bandwidth | Internet / business phone carrier | 2013 |
| 909-917 | MetroPCS (T-Mobile) | Mobile carrier | 2002 |
| 909-923 | Frontier | Local phone company | – |
| 909-930 | Frontier | Local phone company | – |
| 909-933 | Frontier | Local phone company | – |
| 909-934 | 33 Wireless | Mobile carrier | – |
| 909-935 | Matrix Telecom, Llc. S/i/i Tnci | Internet / business phone carrier | – |
| 909-937 | Frontier | Local phone company | – |
| 909-938 | Verizon Wireless | Mobile carrier | – |
| 909-947 | Frontier | Local phone company | – |
| 909-952 | MetroPCS (T-Mobile) | Mobile carrier | 2001 |
| 909-957 | Verizon Wireless | Mobile carrier | – |
| 909-966 | Fractel | Internet / business phone carrier | 2019 |
| 909-969 | AT&T (local phone) | Local phone company | – |
| 909-972 | Level 3 (Lumen) | Internet / business phone carrier | – |
| 909-974 | Frontier | Local phone company | – |
| 909-975 | Frontier | Local phone company | – |
| 909-983 | Frontier | Local phone company | – |
| 909-984 | Frontier | Local phone company | – |
| 909-986 | Frontier | Local phone company | – |
| 909-988 | Frontier | Local phone company | – |
| 909-994 | MetroPCS (T-Mobile) | Mobile carrier | – |
| 909-995 | Utility Telecom Group | Phone company | – |
| 909-996 | AT&T Mobility | Mobile carrier | 2001 |
Most prefixes are pooled: the 10,000 numbers in each are handed out in blocks of 1,000 to different carriers, and people can also take their numbers to another carrier. So the carrier shown is where the prefix started, not a guarantee about any one number. Source: NANPA central office code records, 2026-10-10.