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Diamond Bar, CA Area Codes
Diamond Bar, California (population 51,884) uses area codes 909 and 840.
Carriers with Diamond Bar numbers
32 prefixes are assigned to the Diamond Bar exchange: 6% mobile, 41% VoIP and cable, 53% landline.
| Carrier | Prefixes |
|---|---|
| Frontier | 12 |
| Onvoy (Sinch) | 4 |
| Bandwidth | 3 |
| Lumen (Level 3) | 2 |
| Verizon Business (MCImetro) | 2 |
| Tpx Communications | 2 |
| Charter Ip Enabled Services | 1 |
| Twc Ip Enabled Services | 1 |
Area codes used in Diamond Bar
| Area code | Prefixes serving Diamond Bar | Main carriers in this code |
|---|---|---|
| 909 | 28 | Frontier, T-Mobile, AT&T Mobility |
| 840 | 4 | T-Mobile, Fractel, Onvoy (Sinch) |
Diamond Bar phone number prefixes
Numbers starting with these first six digits were originally assigned to the Diamond Bar exchange.
909-274Charter Ip Enabled Services909-323Onvoy (Sinch)909-345Bandwidth909-348Lumen (Level 3)909-378Verizon Business (MCImetro)909-396Frontier909-444Frontier909-468Frontier909-551Twc Ip Enabled Services909-569AT&T (Teleport)909-594Frontier909-595Frontier909-598Frontier909-610Verizon Business (MCImetro)909-612Frontier909-616AT&T Mobility909-655Bandwidth909-718Tpx Communications909-760Onvoy (Sinch)909-839Frontier909-859AT&T (Pacific Bell)909-860Frontier909-861Frontier909-869Frontier909-895Lumen (Level 3)909-914Bandwidth909-978Tpx Communications909-979Frontier840-240Onvoy (Sinch)840-244T-Mobile840-289Onvoy (Sinch)840-588Fractel
Nearby cities in area code 909
- San Bernardino
- Fontana
- Ontario
- Rancho Cucamonga
- Pomona
- Rialto
- Chino
- Upland
- Chino Hills
- Redlands
- Eastvale
- Highland
Questions
- What is the area code for Diamond Bar, CA?
- Diamond Bar uses 2 area codes: 909 and 840. They overlay each other, so all of them cover the whole city and you dial 10 digits for local calls.
- What time zone is Diamond Bar in?
- Diamond Bar is in the Pacific time zone.