{"area_code":"303","type":"geographic","status":"active","country":"US","region":"Colorado","region_code":"CO","principal_city":"Denver","cities":["Denver","Aurora","Lakewood","Thornton","Arvada","Westminster","Boulder","Longmont","Loveland","Broomfield","Castle Rock","Commerce City","Parker","Littleton","Northglenn","Brighton","Castlewood","Columbine","Englewood","Highlands Ranch","Ken Caryl","Lafayette","Southglenn","Wheat Ridge"],"timezone":"America/Denver","timezone_label":"Mountain Time","current_local_time":"2026-08-05 15:48:19","ten_digit_dialing":true,"service_type":null,"overlay_codes":["720","983"],"nearby_codes":["720","983","748","970","719","307"],"summary":"Area code 303 covers Denver and nearby cities including Aurora, Lakewood, Thornton in Colorado, in the Mountain Time.","carrier_summary":{"nxx_prefixes":785,"blocks":3057,"wireless_pct":31,"top_carriers":[{"name":"QWEST CORPORATION","blocks":855},{"name":"T-MOBILE USA, INC.","blocks":375},{"name":"LEVEL 3 COMMUNICATIONS, LLC - CO","blocks":325},{"name":"CELLCO PARTNERSHIP DBA VERIZON WIRELESS - CO","blocks":324},{"name":"ONVOY, LLC - CO","blocks":231},{"name":"TELEPORT COMMUNICATIONS AMERICA, LLC - CO","blocks":210}],"per_number":"https://areacode.fyi/api/v1/carrier/{number}"},"canonical_url":"https://areacode.fyi/303","source":"North American Numbering Plan Administrator via areacode.fyi","data_date":"2026-08-02"}