303 Area Code — Denver, Colorado

Area code 303 serves Denver, CO.

Most looked-up 303 numbers

• 303-484-1133
• 303-521-3322
• 303-301-3697

Phone prefixes in 303

• 303-484
• 303-521
• 303-301

Carriers serving 303

• Ip Horizon, LLC (1 numbers)
• At&t (1 numbers)
• Comcast Ip Phone, LLC (1 numbers)

Frequently asked questions

Where is area code 303?

Area code 303 serves Denver, CO.

What prefixes are in area code 303?

Phone2.io tracks 3 phone prefixes in area code 303, with carrier and spam-report data on individual numbers.

More about area code 303

Area code 303 overview, history, and local numbers · Get a CO phone number

Last updated: April 4, 2026