Discovering the truth about a phone number, email, or address history can be eye-opening, please use this tool with caution.USA Area code 303 - Denver, CO
Area code 303 is a North American Numbering Plan telephone area code serving Colorado telephone area codes in Colorado. It was activated in 1947 and today covers roughly 740,613 residents across 1 cities and towns .
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Who called me from area code 303?
A call from area code 303 most likely originates from Denver or elsewhere in Colorado - but caller ID spoofing means the area code alone cannot confirm who called. Right now, 25 303 numbers carry scam reports on this page. The only reliable way to identify the caller is to check the full 10-digit number:
- Run the number through the reverse phone lookup at the top of this page to see the owner's name, carrier, and location.
- Compare it against the recently reported scam numbers in 303 below.
- If the call was unwanted, report it to the FTC and use the report form on this page so other 303 residents see it.
Report a scam call from 303 Help other 303-area residents - takes 20 seconds, no signup
Reports are reviewed by our team before appearing on the page. The highest-reported numbers get added to the “Recently reported scam numbers” list above with a “community” badge.
Should I answer a call from a 303 number? Take the 30-second quiz - 5 questions, verdict + advice
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Next step: run a reverse-phone lookup on the number to see everything public about it.
Where is the 303 area code? Coverage map
The pin marks Denver, the largest city served by area code 303. Zoom and pan to explore the coverage region.
Interactive map. Click a pin for city details. Data © OpenStreetMap contributors.
Area codes near 303 (overlay + neighboring)
If a caller ID shows one of these codes, the call is probably still from the Denver area or a nearby region. Click any code to see its own page.
303 area code robocall complaints (FCC data)
Monthly count of FCC complaints tagged to numbers in area code 303 over the last 12 months.
1,767 complaints in the last 12 months. That's about 1523% more robocall complaints per capita than the US average - 239 per 100,000 residents vs a national average of 14.7.
Source: FCC Consumer Complaint Data (dataset vakf-fz8e). Data as of August 9, 2026. Refreshed monthly.
How 303 area code spam calls arrive
Based on 1767 FCC complaints in the last 12 months, here's how 303 spam calls reached recipients:
FCC Consumer Complaint Data, last 12 months as of August 9, 2026. Refreshed monthly. Note: the FCC dataset labels method (Live Voice / Prerecorded / SMS) but does not classify scam type (IRS impersonation, tech support fraud, etc.) - those come from community reports.
Recently reported scam numbers in 303
Numbers reported to the FCC or by our community in the last 12 months. Click any to run a full reverse-phone lookup.
Source: FCC Consumer Complaint Data, last 12 months as of August 9, 2026. Refreshed monthly. Numbers submitted via the report form near the top of this page get added here with a “community” badge after moderation.
How to block 303 spam calls (by carrier)
Getting repeated spam calls from 303 numbers around Denver, Colorado? You can't legitimately block every 303 call without also missing legitimate ones from Denver, Colorado - so the practical fix is to turn on your carrier's free spam filter and register on the national do-not-call list. Step-by-step for each major US carrier below.
AT&T
- Download the free AT&T ActiveArmor app (iOS + Android).
- Sign in with your wireless number.
- Enable Fraud Blocking and Suspected Spam Warning.
- To block a specific number, tap the call in your history → Block.
Verizon
- Download the free Verizon Call Filter app (iOS + Android).
- Sign in with your Verizon account.
- Turn on Spam Filter.
- To block a specific number: My Verizon → Blocks → Add Number.
T-Mobile
- Download the free Scam Shield app (iOS + Android).
- Enable Scam Block (blocks known scam calls silently).
- Use Scam ID to see “Scam Likely” caller ID on suspicious numbers.
- To block a specific number, dial
#662#from your device.
All carriers
- Register on the FTC's National Do-Not-Call list.
- Report unwanted calls to the FCC at fcc.gov/complaints.
- On iPhone: Settings → Phone → Silence Unknown Callers.
- On Android: Phone app → ⋮ → Settings → Caller ID & spam.
Sources: carrier support pages (AT&T, Verizon, T-Mobile), FCC consumer guides. Free features as of 2026. Every one of these steps costs nothing.
History of the 303 area code
state of Colorado. The numbering plan area (NPA) comprises Denver and Boulder, as well as their surrounding suburbs, including Lakewood, Littleton, Longmont, Broomfield, Aurora, and Castle Rock. Area code 303 is the original area code of the NPA, as well as for the entire state, reduced in geographic extent over time.
303 area code FAQ: common questions
What area code is 303?
Area code 303 is a North American Numbering Plan area code that serves Colorado telephone area codes in Colorado, primarily including Denver and surrounding communities. It was activated in 1947.
Where does area code 303 cover?
Area code 303 covers the Denver, Colorado area.
Is 303 a real area code or a scam?
303 is a real, actively-assigned US area code - not itself a scam. However, spammers do use 303 numbers because the code is well-known and appears local to millions of residents. Always verify the specific number, not the area code.
How do I block 303 spam calls?
You cannot legitimately block an entire area code without also blocking legitimate calls from Denver. Better options: register on the National Do-Not-Call list, enable your carrier's spam-filter (all major US carriers now offer this free), and report unwanted calls to the FCC at fcc.gov/complaints so they show up in the trend data on this page.
Sources
Or explore reverse-phone lookup for any US number.