Area Code Lookup
What Area Code Is Rialto?
2 area codes serve Rialto · California
Rialto is served by area codes 840, 909. It is located in California.
Area Codes Serving Rialto
Frequently Asked Questions
What area code is Rialto?
Rialto is served by area codes 840, 909. It is located in California.
Why does Rialto have multiple area codes?
As demand for phone numbers increased, NANPA added area codes through splits (dividing the region) or overlays (layering a new code over the same geography). Rialto now has 2 area codes — 840 and 909 — covering the same or overlapping areas.
How do I call Rialto from outside the US?
To call Rialto from abroad, dial +1 followed by the area code and 7-digit local number (e.g. +1-840-XXX-XXXX). The +1 is the country code for all NANPA countries.