Verified Nov 1, 2026 · Source: NANPA CO Code Assignment Records

Area code 303 prefixes

784 of the 786 possible NXX blocks are assigned in area code 303 (99.7% of capacity), spread across 13 rate centers and 27 holders. The largest holders are QWEST CORPORATION (448 blocks, 57.1%), CELLCO PARTNERSHIP DBA VERIZON WIRELESS - CO (60 blocks, 7.7%), LEVEL 3 COMMUNICATIONS, LLC - CO (58 blocks, 7.4%). Grouped by brand, Lumen accounts for 508 blocks; brand-attributable holders cover 98% of the code, and the rest are CLECs, VoIP wholesalers and regional carriers that trade under their own names. The assignment records here run from 2001-04-12 to 2025-01-16, with 7 blocks handed out in 2006 alone. 228 blocks (29%) are in thousands-block pooling, meaning the block is shared between carriers in 1,000-number lots rather than held whole – which is why a single NXX can serve several carriers at once. 16 were growth assignments – additional blocks to a carrier that had already filled its earlier ones.

784 assigned blocks of 786

13 rate centers

27 holders of record

29% in thousands-block pooling

Largest holders in 303

Holder of record, as NANPA names it	Brand	Blocks	Share
QWEST CORPORATION	Lumen	448	57.1%
CELLCO PARTNERSHIP DBA VERIZON WIRELESS - CO	Verizon	60	7.7%
LEVEL 3 COMMUNICATIONS, LLC - CO	Lumen	58	7.4%
T-MOBILE USA, INC.	T-Mobile	39	5%
NEW CINGULAR WIRELESS PCS, LLC	AT&T	35	4.5%
SPOK, INC.	Spok	31	4%
MCIMETRO ACCESS TRANSMISSION SERVICES LLC	Verizon	31	4%
TELEPORT COMMUNICATIONS AMERICA, LLC - CO	AT&T	28	3.6%
ONVOY, LLC - CO	Onvoy	14	1.8%
AMERICAN MESSAGING SERVICES, LLC	American Messaging	11	1.4%
COMCAST IP PHONE, LLC	Comcast	7	0.9%
ELECTRIC LIGHTWAVE LLC DBA ALLSTREAM	Allstream	3	0.4%

Names are printed as they appear in the assignment records, which is the legal entity rather than the brand. Holding a block is not the same as serving the numbers in it: portability moves numbers between carriers and pooling splits a block between several.

Rate centers with their own page

Rate centers where at least three blocks are assigned, excluding the numbered metro zone codes. The remainder are in the full table below.

DENVER 735 LONGMONT 18 FORTLUPTON 11 DECKERS 5 KEENESBURG 3

All 784 assigned blocks

One row per NXX. “Pooled” means carriers draw 1,000-number lots from the block rather than holding all 10,000, so a pooled prefix can belong to several carriers at once. “Not in service” means assigned but not yet open for calls – a caller ID from one of those is necessarily spoofed. The holder column gives the brand where the legal entity maps to one; the full legal names are in the holders table above, exactly as NANPA records them.

Prefix	Holder of record	Rate center	Assigned	Pooled	In service
303-200	AT&T	DENVER	–	yes	yes
303-201	Spok	DENVER	–	–	yes
303-202	Lumen	DENVER	–	–	yes
303-203	American Messaging	DENVER	–	–	yes
303-204	Verizon	DENVER	–	–	yes
303-205	Lumen	DENVER	–	–	yes
303-206	Spok	DENVER	–	–	yes
303-207	Spok	DENVER	–	–	yes
303-208	Spok	DENVER	–	–	yes
303-209	Verizon	DENVER	–	–	yes
303-210	T-Mobile	DENVER	–	yes	yes
303-212	American Messaging	DENVER	–	–	yes
303-213	Spok	DENVER	–	–	yes
303-214	Verizon	DENVER	–	yes	yes
303-215	Lumen	DENVER	–	–	yes
303-216	Lumen	DENVER	–	–	yes
303-217	Verizon	DENVER	–	yes	yes
303-218	Verizon	DENVER	–	yes	yes
303-219	Verizon	DENVER	–	yes	yes
303-220	Lumen	DENVER	–	–	yes
303-221	Lumen	DENVER	–	–	yes
303-222	Verizon	DENVER	–	–	yes
303-223	Lumen	DENVER	–	–	yes
303-224	Lumen	DENVER	–	–	yes
303-225	Lumen	DENVER	–	yes	yes
303-226	Lumen	DENVER	–	–	yes
303-227	Lumen	DENVER	–	–	yes
303-228	Lumen	DENVER	–	–	yes
303-229	Verizon	DENVER	–	–	yes
303-230	Spok	DENVER	–	–	yes
303-231	Lumen	DENVER	–	–	yes
303-232	Lumen	DENVER	–	–	yes
303-233	Lumen	DENVER	–	–	yes
303-234	Lumen	DENVER	–	–	yes
303-235	Lumen	DENVER	–	–	yes
303-236	Lumen	DENVER	–	–	yes
303-237	Lumen	DENVER	–	–	yes
303-238	Lumen	DENVER	–	–	yes
303-239	Lumen	DENVER	–	–	yes
303-240	Spok	DENVER	–	–	yes
303-241	Verizon	DENVER	–	–	yes
303-242	Verizon	DENVER	–	yes	yes
303-243	N.E. COLORADO CELLULAR, INC.	DENVER	–	yes	yes
303-244	Lumen	DENVER	–	–	yes
303-245	Lumen	DENVER	–	–	yes
303-246	T-Mobile	DENVER	–	yes	yes
303-247	Lumen	DENVER	–	–	yes
303-248	AT&T	DENVER	–	yes	yes
303-249	AT&T	DENVER	–	–	yes
303-250	AT&T	DENVER	–	–	yes
303-251	Spok	DENVER	–	–	yes
303-252	Lumen	DENVER	–	–	yes
303-253	AT&T	DENVER	–	yes	yes
303-254	Lumen	DENVER	–	–	yes
303-255	Lumen	DENVER	–	–	yes
303-256	AT&T	DENVER	–	–	yes
303-257	T-Mobile	DENVER	–	yes	yes
303-258	Lumen	DENVER	–	yes	yes
303-259	American Messaging	DENVER	–	–	yes
303-260	Lumen	DENVER	–	yes	yes
303-261	Lumen	DENVER	–	yes	yes
303-262	AT&T	DENVER	–	–	yes
303-263	Verizon	DENVER	–	–	yes
303-264	AT&T	DENVER	–	yes	yes
303-265	Lumen	DENVER	–	yes	yes
303-266	Spok	DENVER	–	–	yes
303-267	Lumen	DENVER	–	–	yes
303-268	Lumen	DENVER	–	–	yes
303-269	Lumen	DENVER	–	yes	yes
303-270	Lumen	DENVER	–	–	yes
303-271	Lumen	DENVER	–	–	yes
303-272	Lumen	DENVER	–	–	yes
303-273	Lumen	DENVER	–	–	yes
303-274	Lumen	DENVER	–	–	yes
303-275	Lumen	DENVER	–	–	yes
303-276	Onvoy	DENVER	2021-08-19	yes	yes
303-277	Lumen	DENVER	–	–	yes
303-278	Lumen	DENVER	–	–	yes
303-279	Lumen	DENVER	–	–	yes
303-280	Lumen	DENVER	–	–	yes
303-281	Lumen	DENVER	–	–	yes
303-282	Lumen	DENVER	–	–	yes
303-283	Lumen	DENVER	–	–	yes
303-284	Comcast	DENVER	–	yes	yes
303-285	Lumen	DENVER	–	–	yes
303-286	Lumen	DENVER	–	–	yes
303-287	Lumen	DENVER	–	–	yes
303-288	Lumen	DENVER	–	–	yes
303-289	Lumen	DENVER	–	–	yes
303-290	Lumen	DENVER	–	–	yes
303-291	Lumen	DENVER	–	–	yes
303-292	Lumen	DENVER	–	–	yes
303-293	Lumen	DENVER	–	–	yes
303-294	Lumen	DENVER	–	–	yes
303-295	Lumen	DENVER	–	–	yes
303-296	Lumen	DENVER	–	–	yes
303-297	Lumen	DENVER	–	–	yes
303-298	Lumen	DENVER	–	–	yes
303-299	Lumen	DENVER	–	–	yes
303-300	Lumen	DENVER	–	–	yes
303-301	Lumen	DENVER	–	yes	yes
303-302	Verizon	DENVER	–	–	yes
303-303	HD CARRIER LLC	DENVER	2024-08-26	yes	yes
303-304	AT&T	FORTLUPTON	2004-11-18	yes	yes
303-305	Verizon	DENVER	–	yes	yes
303-306	Lumen	DENVER	–	yes	yes
303-307	Lumen	DENVER	–	–	yes
303-308	Lumen	DENVER	–	–	yes
303-309	Lumen	DENVER	–	yes	yes
303-310	American Messaging	DENVER	–	–	yes
303-312	Lumen	DENVER	–	–	yes
303-313	Lumen	DENVER	–	–	yes
303-314	Lumen	DENVER	–	yes	yes
303-315	Lumen	DENVER	–	–	yes
303-316	Lumen	DENVER	–	yes	yes
303-317	Lumen	DENVER	–	yes	yes
303-318	Lumen	DENVER	–	–	yes
303-319	ELBERT COUNTY WIRELESS, LLC	DENVER	2004-08-12	yes	yes
303-320	Lumen	DENVER	–	–	yes
303-321	Lumen	DENVER	–	–	yes
303-322	Lumen	DENVER	–	–	yes
303-323	Verizon	DENVER	–	yes	yes
303-324	AT&T	DENVER	–	–	yes
303-325	Lumen	DENVER	–	yes	yes
303-326	Lumen	DENVER	–	–	yes
303-327	Lumen	DENVER	–	yes	yes
303-328	Verizon	DENVER	–	yes	yes
303-329	Lumen	DENVER	–	–	yes
303-330	Onvoy	DENVER	2006-03-09	yes	yes
303-331	Lumen	DENVER	–	–	yes
303-332	T-Mobile	DENVER	–	–	yes
303-333	Lumen	DENVER	–	–	yes
303-334	Verizon	DENVER	–	–	yes
303-335	Verizon	DENVER	–	yes	yes
303-336	Lumen	DENVER	–	–	yes
303-337	Lumen	DENVER	–	–	yes
303-338	Lumen	DENVER	–	–	yes
303-339	Onvoy	DENVER	–	yes	yes
303-340	Lumen	DENVER	–	–	yes
303-341	Lumen	DENVER	–	–	yes
303-342	Lumen	DENVER	–	–	yes
303-343	Lumen	DENVER	–	–	yes
303-344	Lumen	DENVER	–	–	yes
303-345	Lumen	DENVER	–	yes	yes
303-346	Lumen	DENVER	–	–	yes
303-347	Lumen	DENVER	–	–	yes
303-348	Lumen	DENVER	–	yes	yes
303-349	Verizon	DENVER	–	–	yes
303-350	AT&T	DENVER	–	yes	yes
303-351	Onvoy	DECKERS	2006-11-08	yes	yes
303-352	Lumen	DENVER	–	–	yes
303-353	Comcast	DENVER	–	yes	yes
303-354	AT&T	DENVER	–	yes	yes
303-355	Lumen	DENVER	–	–	yes
303-356	T-Mobile	DENVER	–	yes	yes
303-357	Verizon	DENVER	–	yes	yes
303-358	Verizon	DENVER	–	–	yes
303-359	T-Mobile	DENVER	–	–	yes
303-360	Lumen	DENVER	–	–	yes
303-361	Lumen	DENVER	–	–	yes
303-362	AT&T	DENVER	–	yes	yes
303-363	Lumen	DENVER	–	–	yes
303-364	Lumen	DENVER	–	–	yes
303-365	Lumen	DENVER	–	–	yes
303-366	Lumen	DENVER	–	–	yes
303-367	Lumen	DENVER	–	–	yes
303-368	Lumen	DENVER	–	–	yes
303-369	Lumen	DENVER	–	–	yes
303-370	Lumen	DENVER	–	–	yes
303-371	Lumen	DENVER	–	–	yes
303-372	Lumen	DENVER	–	–	yes
303-373	Lumen	DENVER	–	–	yes
303-374	AT&T	DENVER	–	yes	yes
303-375	Lumen	DENVER	–	–	yes
303-376	Lumen	DENVER	–	–	yes
303-377	Lumen	DENVER	–	–	yes
303-378	AT&T	DENVER	–	–	yes
303-379	AT&T	DENVER	–	yes	yes
303-380	Lumen	DENVER	–	–	yes
303-381	Lumen	DENVER	–	–	yes
303-382	Lumen	DENVER	–	–	yes
303-383	Lumen	DENVER	–	–	yes
303-384	Lumen	DENVER	–	–	yes
303-385	Lumen	DENVER	–	yes	yes
303-386	Lumen	DENVER	–	yes	yes
303-387	Lumen	DENVER	–	–	yes
303-388	Lumen	DENVER	–	–	yes
303-389	Lumen	DENVER	–	yes	yes
303-390	Verizon	DENVER	–	–	yes
303-391	Lumen	DENVER	–	–	yes
303-392	Verizon	DENVER	2025-01-16	yes	yes
303-393	Lumen	DENVER	–	–	yes
303-394	Lumen	DENVER	–	–	yes
303-395	Lumen	DENVER	–	–	yes
303-396	LIVE WIRE NETWORKS, INC. - CO	DENVER	2005-06-01	yes	yes
303-397	Lumen	DENVER	–	–	yes
303-398	Lumen	DENVER	–	–	yes
303-399	Lumen	DENVER	–	–	yes
303-400	Lumen	DENVER	–	–	yes
303-401	Lumen	DENVER	–	yes	yes
303-402	Lumen	DENVER	–	–	yes
303-403	Lumen	DENVER	–	–	yes
303-404	Lumen	DENVER	–	–	yes
303-405	Lumen	DENVER	–	–	yes
303-406	Lumen	DENVER	–	yes	yes
303-407	Onvoy	DENVER	–	–	yes
303-408	AT&T	DENVER	–	yes	yes
303-409	Lumen	DENVER	–	yes	yes
303-410	Lumen	DENVER	–	–	yes
303-412	Lumen	DENVER	–	–	yes
303-413	Lumen	DENVER	–	–	yes
303-414	Lumen	DENVER	–	yes	yes
303-415	Lumen	DENVER	–	–	yes
303-416	Lumen	DENVER	–	yes	yes
303-417	Lumen	DENVER	–	–	yes
303-418	Lumen	DENVER	–	yes	yes
303-419	T-Mobile	DENVER	–	yes	yes
303-420	Lumen	DENVER	–	–	yes
303-421	Lumen	DENVER	–	–	yes
303-422	Lumen	DENVER	–	–	yes
303-423	Lumen	DENVER	–	–	yes
303-424	Lumen	DENVER	–	–	yes
303-425	Lumen	DENVER	–	–	yes
303-426	Lumen	DENVER	–	–	yes
303-427	Lumen	DENVER	–	–	yes
303-428	Lumen	DENVER	–	–	yes
303-429	Lumen	DENVER	–	–	yes
303-430	Lumen	DENVER	–	–	yes
303-431	Lumen	DENVER	–	–	yes
303-432	Lumen	DENVER	–	–	yes
303-433	Lumen	DENVER	–	–	yes
303-434	T-Mobile	DENVER	–	yes	yes
303-435	T-Mobile	DENVER	–	yes	yes
303-436	Lumen	DENVER	–	–	yes
303-437	T-Mobile	DENVER	–	yes	yes
303-438	Lumen	DENVER	–	–	yes
303-439	Lumen	DENVER	–	–	yes
303-440	Lumen	DENVER	–	–	yes
303-441	Lumen	DENVER	–	–	yes
303-442	Lumen	DENVER	–	–	yes
303-443	Lumen	DENVER	–	–	yes
303-444	Lumen	DENVER	–	–	yes
303-445	Lumen	DENVER	–	–	yes
303-446	Lumen	DENVER	–	–	yes
303-447	Lumen	DENVER	–	–	yes
303-448	Lumen	DENVER	–	–	yes
303-449	Lumen	DENVER	–	–	yes
303-450	Lumen	DENVER	–	–	yes
303-451	Lumen	DENVER	–	–	yes
303-452	Lumen	DENVER	–	–	yes
303-453	Lumen	DENVER	–	yes	yes
303-454	Lumen	DENVER	–	–	yes
303-455	Lumen	DENVER	–	–	yes
303-456	Lumen	DENVER	–	–	yes
303-457	Lumen	DENVER	–	yes	yes
303-458	Lumen	DENVER	–	–	yes
303-459	Lumen	DENVER	–	yes	yes
303-460	Lumen	DENVER	–	–	yes
303-461	Spok	DENVER	–	–	yes
303-462	Lumen	DENVER	–	–	yes
303-463	Lumen	DENVER	–	–	yes
303-464	Lumen	DENVER	–	–	yes
303-465	Lumen	DENVER	–	–	yes
303-466	Lumen	DENVER	–	–	yes
303-467	Lumen	DENVER	–	–	yes
303-468	Onvoy	DENVER	–	yes	yes
303-469	Lumen	DENVER	–	–	yes
303-470	Lumen	DENVER	–	–	yes
303-471	Lumen	DENVER	–	–	yes
303-472	T-Mobile	DENVER	–	yes	yes
303-473	Lumen	DENVER	–	–	yes
303-474	AT&T	DENVER	–	yes	yes
303-475	AT&T	DENVER	–	–	yes
303-476	Verizon	DENVER	–	yes	yes
303-477	Lumen	DENVER	–	–	yes
303-478	AT&T	DENVER	–	–	yes
303-479	AT&T	DENVER	–	yes	yes
303-480	Lumen	DENVER	–	–	yes
303-481	Verizon	DENVER	–	yes	yes
303-482	Lumen	DENVER	–	yes	yes
303-483	Lumen	DENVER	–	yes	yes
303-484	AT&T	DENVER	–	yes	yes
303-485	Lumen	LONGMONT	–	–	yes
303-486	Lumen	DENVER	–	–	yes
303-487	Lumen	DENVER	–	–	yes
303-488	Lumen	DENVER	–	–	yes
303-489	Verizon	DENVER	–	–	yes
303-490	Spok	DENVER	–	–	yes
303-491	Charter	DENVER	2022-05-03	yes	yes
303-492	Lumen	DENVER	–	–	yes
303-493	Lumen	DENVER	–	yes	yes
303-494	Lumen	DENVER	–	–	yes
303-495	Verizon	DENVER	–	yes	yes
303-496	Verizon	DENVER	2004-04-08	yes	yes
303-497	Lumen	DENVER	–	–	yes
303-498	Comcast	DENVER	2005-04-22	yes	yes
303-499	Lumen	DENVER	–	–	yes
303-500	Lumen	HUDSON	2005-01-04	yes	yes
303-501	Verizon	DENVER	2006-01-26	yes	yes
303-502	Verizon	FORTLUPTON	2005-12-13	yes	yes
303-503	Verizon	DENVER	–	–	yes
303-504	Lumen	DENVER	–	–	yes
303-505	T-Mobile	DENVER	2012-11-09	yes	yes
303-506	AT&T	FORTLUPTON	2001-09-13	yes	yes
303-507	T-Mobile	DENVER	–	yes	yes
303-508	American Messaging	DENVER	–	–	yes
303-509	American Messaging	DENVER	–	–	yes
303-510	American Messaging	DENVER	–	–	yes
303-512	Lumen	DENVER	–	yes	yes
303-513	AT&T	DENVER	2002-02-15	–	yes
303-514	Verizon	DENVER	–	–	yes
303-515	Onvoy	DENVER	2011-11-14	yes	yes
303-516	Lumen	DENVER	–	–	yes
303-517	AT&T	DENVER	–	–	yes
303-518	Verizon	DENVER	–	–	yes
303-519	Verizon	DENVER	–	yes	yes
303-520	T-Mobile	DENVER	–	yes	yes
303-521	T-Mobile	DENVER	–	yes	yes
303-522	T-Mobile	DENVER	–	yes	yes
303-523	T-Mobile	DENVER	–	–	yes
303-524	AT&T	DENVER	–	yes	yes
303-525	T-Mobile	DENVER	–	yes	yes
303-526	Lumen	DENVER	–	yes	yes
303-527	Lumen	DENVER	–	–	yes
303-528	American Messaging	DENVER	–	–	yes
303-529	Onvoy	DENVER	2019-10-07	yes	yes
303-530	Lumen	DENVER	–	–	yes
303-531	Verizon	DENVER	–	yes	yes
303-532	Windstream	LONGMONT	–	yes	yes
303-533	Lumen	DENVER	–	–	yes
303-534	Lumen	DENVER	–	–	yes
303-535	Onvoy	FORTLUPTON	–	yes	yes
303-536	Lumen	HUDSON	–	yes	yes
303-537	AT&T	DENVER	–	yes	yes
303-538	Lumen	DENVER	–	–	yes
303-539	Verizon	DENVER	–	–	yes
303-540	Spok	DENVER	–	–	yes
303-541	Lumen	DENVER	–	–	yes
303-542	Verizon	DENVER	–	–	yes
303-543	Lumen	DENVER	–	–	yes
303-544	Lumen	DENVER	–	–	yes
303-545	Lumen	DENVER	–	–	yes
303-546	Lumen	DENVER	–	–	yes
303-547	Lumen	DENVER	–	yes	yes
303-548	Verizon	DENVER	–	–	yes
303-549	Verizon	DENVER	–	–	yes
303-550	Verizon	DENVER	–	–	yes
303-551	Verizon	DENVER	–	yes	yes
303-552	Lumen	DENVER	–	yes	yes
303-553	Spok	DENVER	–	–	yes
303-554	Lumen	DENVER	–	–	yes
303-556	Lumen	DENVER	–	–	yes
303-557	Lumen	DENVER	–	yes	yes
303-558	Lumen	DENVER	–	yes	yes
303-559	American Messaging	DENVER	–	–	yes
303-560	Spok	DENVER	–	–	yes
303-561	Lumen	DENVER	–	–	yes
303-562	Lumen	DENVER	–	yes	yes
303-563	Lumen	DENVER	–	yes	yes
303-564	T-Mobile	DENVER	–	–	yes
303-565	Onvoy	DENVER	–	yes	yes
303-566	Verizon	DENVER	–	yes	yes
303-567	Lumen	DENVER	–	yes	yes
303-568	AT&T	DENVER	–	yes	yes
303-569	Lumen	GEORGETOWN	–	yes	yes
303-570	AT&T	DENVER	–	–	yes
303-571	Lumen	DENVER	–	–	yes
303-572	Lumen	DENVER	–	–	yes
303-573	Lumen	DENVER	–	–	yes
303-574	Lumen	DENVER	–	–	yes
303-575	Lumen	DENVER	–	–	yes
303-576	Lumen	DENVER	–	–	yes
303-577	Allstream	DENVER	–	–	yes
303-578	Lumen	KEENESBURG	2006-09-12	yes	yes
303-579	Verizon	DENVER	–	–	yes
303-580	American Messaging	DENVER	–	–	yes
303-581	Lumen	DENVER	–	–	yes
303-582	Lumen	DENVER	–	yes	yes
303-583	AT&T	DENVER	–	–	yes
303-584	Lumen	DENVER	–	–	yes
303-585	Lumen	DENVER	–	yes	yes
303-586	Lumen	DENVER	–	yes	yes
303-587	T-Mobile	DENVER	–	yes	yes
303-588	AT&T	DENVER	–	–	yes
303-589	AT&T	DENVER	–	–	yes
303-590	Lumen	DENVER	–	yes	yes
303-591	T-Mobile	DENVER	–	yes	yes
303-592	Lumen	DENVER	–	–	yes
303-593	AT&T	DENVER	–	yes	yes
303-594	Verizon	DENVER	–	–	yes
303-595	Lumen	DENVER	–	–	yes
303-596	T-Mobile	DENVER	–	yes	yes
303-597	Allstream	DENVER	–	yes	yes
303-598	T-Mobile	DENVER	–	yes	yes
303-599	Spok	DENVER	–	–	yes
303-600	AT&T	DENVER	–	yes	yes
303-601	AT&T	DENVER	–	–	yes
303-602	Lumen	DENVER	–	–	yes
303-603	Lumen	DENVER	–	–	yes
303-604	Lumen	DENVER	–	–	yes
303-605	Lumen	DENVER	–	–	yes
303-606	Lumen	DENVER	–	–	yes
303-607	Lumen	DENVER	–	yes	yes
303-608	Lumen	DENVER	–	–	yes
303-609	Spok	DENVER	–	–	yes
303-610	Spok	DENVER	–	–	yes
303-612	Spok	DENVER	–	–	yes
303-613	Spok	DENVER	–	–	yes
303-614	Lumen	DENVER	–	–	yes
303-615	Lumen	DENVER	–	–	yes
303-616	Charter	KEENESBURG	2021-11-18	yes	yes
303-617	Lumen	DENVER	–	–	yes
303-618	AT&T	DENVER	–	–	yes
303-619	AT&T	DENVER	–	–	yes
303-620	Lumen	DENVER	–	yes	yes
303-621	Lumen	DENVER	–	yes	yes
303-622	STRASBURG TEL. CO.	STRASBURG	–	yes	yes
303-623	Lumen	DENVER	–	–	yes
303-624	Lumen	DENVER	–	–	yes
303-625	Lumen	DENVER	–	yes	yes
303-626	Lumen	DENVER	–	–	yes
303-627	Lumen	DENVER	–	–	yes
303-628	Lumen	DENVER	–	–	yes
303-629	Lumen	DENVER	–	–	yes
303-630	Lumen	DENVER	–	yes	yes
303-632	AT&T	DENVER	–	yes	yes
303-633	Lumen	DENVER	–	–	yes
303-634	Lumen	DENVER	–	–	yes
303-635	Lumen	DENVER	–	yes	yes
303-636	Lumen	DENVER	–	yes	yes
303-637	Lumen	DENVER	–	–	yes
303-638	AT&T	DENVER	–	–	yes
303-639	Lumen	DENVER	–	–	yes
303-640	Lumen	DENVER	–	–	yes
303-641	T-Mobile	DENVER	–	yes	yes
303-642	Lumen	DENVER	–	yes	yes
303-643	Lumen	DENVER	–	yes	yes
303-644	EASTERN SLOPE RURAL TEL. ASSN., INC.	BENNETT	–	–	yes
303-645	Lumen	DENVER	–	yes	yes
303-646	Lumen	DENVER	–	yes	yes
303-647	Lumen	DECKERS	–	yes	yes
303-648	Lumen	DENVER	–	yes	yes
303-649	Lumen	DENVER	–	–	yes
303-650	Lumen	DENVER	–	–	yes
303-651	Lumen	LONGMONT	–	–	yes
303-652	Lumen	LONGMONT	–	yes	yes
303-653	Lumen	DENVER	–	yes	yes
303-654	Lumen	DENVER	–	–	yes
303-655	Lumen	DENVER	–	–	yes
303-656	Verizon	DENVER	–	yes	yes
303-657	Lumen	DENVER	–	–	yes
303-658	Lumen	DENVER	–	yes	yes
303-659	Lumen	DENVER	–	–	yes
303-660	Lumen	DENVER	–	–	yes
303-661	Lumen	DENVER	–	yes	yes
303-662	Lumen	DENVER	–	–	yes
303-663	Lumen	DENVER	–	–	yes
303-664	Lumen	DENVER	–	–	yes
303-665	Lumen	DENVER	–	–	yes
303-666	Lumen	DENVER	–	–	yes
303-667	T-Mobile	DENVER	–	–	yes
303-668	T-Mobile	DENVER	–	–	yes
303-669	T-Mobile	DENVER	–	–	yes
303-670	Lumen	DENVER	–	–	yes
303-671	Lumen	DENVER	–	–	yes
303-672	Lumen	DENVER	–	–	yes
303-673	Lumen	DENVER	–	–	yes
303-674	Lumen	DENVER	–	–	yes
303-675	Lumen	DENVER	–	–	yes
303-676	Lumen	DENVER	–	yes	yes
303-677	Lumen	DENVER	–	–	yes
303-678	Lumen	LONGMONT	–	–	yes
303-679	Lumen	DENVER	–	–	yes
303-680	Lumen	DENVER	–	–	yes
303-681	Lumen	DENVER	–	yes	yes
303-682	Lumen	LONGMONT	–	–	yes
303-683	Lumen	DENVER	–	–	yes
303-684	Lumen	LONGMONT	–	–	yes
303-685	Lumen	DENVER	–	–	yes
303-686	Spok	DENVER	–	–	yes
303-687	Spok	DENVER	–	–	yes
303-688	Lumen	DENVER	–	–	yes
303-689	Lumen	DENVER	–	–	yes
303-690	Lumen	DENVER	–	–	yes
303-691	Lumen	DENVER	–	–	yes
303-692	Lumen	DENVER	–	–	yes
303-693	Lumen	DENVER	–	–	yes
303-694	Lumen	DENVER	–	–	yes
303-695	Lumen	DENVER	–	–	yes
303-696	Lumen	DENVER	–	–	yes
303-697	Lumen	DENVER	–	–	yes
303-698	Lumen	DENVER	–	–	yes
303-699	Lumen	DENVER	–	–	yes
303-701	COMMUNICATIONS UNLIMITED	DENVER	–	–	yes
303-702	Lumen	LONGMONT	–	–	yes
303-703	Lumen	DENVER	–	–	yes
303-704	Verizon	DENVER	–	yes	yes
303-705	Lumen	DENVER	–	–	yes
303-706	Lumen	DENVER	–	–	yes
303-707	Lumen	DENVER	–	–	yes
303-708	Lumen	DENVER	–	–	yes
303-709	Verizon	LONGMONT	–	yes	yes
303-710	Verizon	FORTLUPTON	–	yes	yes
303-712	Lumen	DENVER	–	–	yes
303-713	Lumen	DENVER	–	–	yes
303-714	Lumen	DENVER	–	–	yes
303-715	Lumen	DENVER	–	yes	yes
303-716	Lumen	DENVER	–	–	yes
303-717	AT&T	FORTLUPTON	–	–	yes
303-718	Verizon	FORTLUPTON	–	yes	yes
303-719	Lumen	DEER TRAIL	2006-11-16	yes	yes
303-720	Verizon	FORTLUPTON	2008-06-13	yes	yes
303-721	Lumen	DENVER	–	–	yes
303-722	Lumen	DENVER	–	–	yes
303-723	AT&T	DENVER	–	–	yes
303-724	Lumen	DENVER	–	–	yes
303-725	T-Mobile	DENVER	–	yes	yes
303-726	Verizon	DENVER	–	–	yes
303-727	Lumen	DENVER	–	yes	yes
303-728	AT&T	DENVER	–	yes	yes
303-729	Verizon	DENVER	–	–	yes
303-730	Lumen	DENVER	–	–	yes
303-731	Lumen	DENVER	–	yes	yes
303-732	Lumen	KEENESBURG	–	yes	yes
303-733	Lumen	DENVER	–	–	yes
303-734	Lumen	DENVER	–	–	yes
303-735	Lumen	DENVER	–	–	yes
303-736	AT&T	DENVER	–	yes	yes
303-737	Lumen	DENVER	–	–	yes
303-738	Lumen	DENVER	–	–	yes
303-739	Lumen	DENVER	–	–	yes
303-740	Lumen	DENVER	–	–	yes
303-741	Lumen	DENVER	–	–	yes
303-742	Lumen	DENVER	–	–	yes
303-743	Lumen	DENVER	–	–	yes
303-744	Lumen	DENVER	–	–	yes
303-745	Lumen	DENVER	–	–	yes
303-746	Verizon	LONGMONT	–	yes	yes
303-747	Lumen	ALLNSPKLYN	–	yes	yes
303-748	AT&T	DENVER	–	–	yes
303-749	AT&T	DENVER	–	yes	yes
303-750	Lumen	DENVER	–	–	yes
303-751	Lumen	DENVER	–	–	yes
303-752	Lumen	DENVER	–	–	yes
303-753	Lumen	DENVER	–	–	yes
303-754	Lumen	DENVER	–	–	yes
303-755	Lumen	DENVER	–	–	yes
303-756	Lumen	DENVER	–	–	yes
303-757	Lumen	DENVER	–	–	yes
303-758	Lumen	DENVER	–	–	yes
303-759	Lumen	DENVER	–	–	yes
303-760	Spok	DENVER	–	–	yes
303-761	Lumen	DENVER	–	–	yes
303-762	Lumen	DENVER	–	–	yes
303-763	Lumen	DENVER	–	yes	yes
303-764	Lumen	DENVER	–	–	yes
303-765	Lumen	DENVER	–	–	yes
303-766	Lumen	DENVER	–	–	yes
303-767	American Messaging	DENVER	–	–	yes
303-768	Lumen	DENVER	–	–	yes
303-769	BIJOU TEL. COOP. ASSN., INC.	DEER TRAIL	–	–	yes
303-770	Lumen	DENVER	–	–	yes
303-771	Lumen	DENVER	–	–	yes
303-772	Lumen	LONGMONT	–	–	yes
303-773	Lumen	DENVER	–	–	yes
303-774	Lumen	LONGMONT	–	–	yes
303-775	Verizon	LONGMONT	–	–	yes
303-776	Lumen	LONGMONT	–	–	yes
303-777	Lumen	DENVER	–	–	yes
303-778	Lumen	DENVER	–	–	yes
303-779	Lumen	DENVER	–	–	yes
303-780	Lumen	DENVER	–	–	yes
303-781	Lumen	DENVER	–	–	yes
303-782	Lumen	DENVER	–	–	yes
303-783	Lumen	DENVER	–	–	yes
303-784	Lumen	DENVER	–	–	yes
303-785	Verizon	DENVER	–	–	yes
303-786	Lumen	DENVER	–	–	yes
303-787	Lumen	DENVER	–	–	yes
303-788	Lumen	DENVER	–	–	yes
303-789	Lumen	DENVER	–	–	yes
303-790	Lumen	DENVER	–	–	yes
303-791	Lumen	DENVER	–	–	yes
303-792	Lumen	DENVER	–	–	yes
303-793	Lumen	DENVER	–	–	yes
303-794	Lumen	DENVER	–	–	yes
303-795	Lumen	DENVER	–	–	yes
303-796	Lumen	DENVER	–	–	yes
303-797	Lumen	DENVER	–	–	yes
303-798	Lumen	DENVER	–	–	yes
303-799	Lumen	DENVER	–	–	yes
303-800	Lumen	DENVER	–	–	yes
303-801	Verizon	DENVER	–	yes	yes
303-802	Lumen	DENVER	–	yes	yes
303-803	Lumen	DENVER	–	yes	yes
303-804	Lumen	DENVER	–	–	yes
303-805	Lumen	DENVER	–	–	yes
303-806	Lumen	DENVER	–	–	yes
303-807	AT&T	DENVER	–	–	yes
303-808	AT&T	DENVER	–	–	yes
303-809	AT&T	DENVER	–	–	yes
303-810	AT&T	DENVER	–	–	yes
303-812	Lumen	DENVER	–	–	yes
303-813	Lumen	DENVER	–	–	yes
303-814	Lumen	DENVER	–	–	yes
303-815	INTERLINK ADV SVC DBA FORETHOUGHT.NET - CO	DENVER	2005-02-03	yes	yes
303-816	Lumen	DECKERS	–	yes	yes
303-817	Verizon	DENVER	–	–	yes
303-818	Verizon	DENVER	–	–	yes
303-819	Verizon	DENVER	–	–	yes
303-820	Lumen	DENVER	–	–	yes
303-821	Spok	DENVER	–	–	yes
303-822	BIJOU TEL. COOP. ASSN., INC.	BYERS	–	–	yes
303-823	Lumen	ALLNSPKLYN	–	yes	yes
303-824	AT&T	DENVER	–	yes	yes
303-825	Lumen	DENVER	–	–	yes
303-826	Spok	DENVER	–	–	yes
303-827	Lumen	LONGMONT	–	yes	yes
303-828	Lumen	DENVER	–	yes	yes
303-829	Verizon	DENVER	–	–	yes
303-830	Lumen	DENVER	–	yes	yes
303-831	Lumen	DENVER	–	–	yes
303-832	Lumen	DENVER	–	–	yes
303-833	Lumen	DENVER	–	–	yes
303-834	Verizon	LONGMONT	2006-09-27	yes	yes
303-835	Lumen	DENVER	–	yes	yes
303-836	COMMUNICATIONS UNLIMITED	DENVER	–	–	yes
303-837	Lumen	DENVER	–	–	yes
303-838	Lumen	DECKERS	–	–	yes
303-839	Lumen	DENVER	–	–	yes
303-840	Lumen	DENVER	–	–	yes
303-841	Lumen	DENVER	–	–	yes
303-842	Verizon	DENVER	–	yes	yes
303-843	Lumen	DENVER	–	–	yes
303-844	Lumen	DENVER	–	–	yes
303-845	AT&T	LONGMONT	–	yes	yes
303-846	Lumen	DENVER	–	–	yes
303-847	Lumen	DENVER	–	yes	yes
303-848	Lumen	LONGMONT	–	yes	yes
303-849	ROGGEN TEL. COOP. CO.	ROGGEN	–	–	yes
303-850	Lumen	DENVER	–	–	yes
303-851	Spok	DENVER	–	–	yes
303-852	Spok	DENVER	–	–	yes
303-853	Lumen	DENVER	–	–	yes
303-854	Lumen	DENVER	–	yes	yes
303-855	Spok	DENVER	–	–	yes
303-856	Lumen	DENVER	–	yes	yes
303-857	Lumen	FORTLUPTON	–	yes	yes
303-858	Lumen	DENVER	–	–	yes
303-859	Verizon	DENVER	–	yes	yes
303-860	Lumen	DENVER	–	–	yes
303-861	Lumen	DENVER	–	–	yes
303-862	Comcast	DENVER	2005-06-04	yes	yes
303-863	Lumen	DENVER	–	–	yes
303-864	Lumen	DENVER	–	–	yes
303-865	Lumen	DENVER	–	yes	yes
303-866	Lumen	DENVER	–	–	yes
303-867	ILOKA, INC. DBA NEWCLOUD NETWORKS - CO	DENVER	2005-11-04	yes	yes
303-868	Verizon	DENVER	–	–	yes
303-869	Lumen	DENVER	–	–	yes
303-870	Verizon	DENVER	–	–	yes
303-871	Lumen	DENVER	–	–	yes
303-872	Lumen	DENVER	–	yes	yes
303-873	Lumen	DENVER	–	–	yes
303-874	Lumen	DENVER	–	yes	yes
303-875	T-Mobile	DENVER	–	–	yes
303-876	Verizon	DENVER	–	–	yes
303-877	Verizon	DENVER	–	–	yes
303-878	Spok	DENVER	–	–	yes
303-879	Onvoy	DENVER	2023-08-15	yes	yes
303-880	Verizon	DENVER	–	–	yes
303-881	AT&T	DENVER	–	–	yes
303-882	AT&T	DENVER	–	–	yes
303-883	AT&T	DENVER	–	–	yes
303-884	AT&T	DENVER	–	–	yes
303-885	AT&T	DENVER	2001-04-12	–	yes
303-886	AT&T	DENVER	2001-04-12	–	yes
303-887	AT&T	DENVER	2001-04-12	–	yes
303-888	AT&T	DENVER	–	–	yes
303-889	Lumen	DENVER	–	yes	yes
303-890	Spok	DENVER	–	–	yes
303-891	Spok	DENVER	–	–	yes
303-892	Lumen	DENVER	–	–	yes
303-893	Lumen	DENVER	–	–	yes
303-894	Lumen	DENVER	–	–	yes
303-895	Verizon	DENVER	–	yes	yes
303-896	Lumen	DENVER	–	–	yes
303-897	Spok	DENVER	–	–	yes
303-898	AT&T	DENVER	–	–	yes
303-899	Lumen	DENVER	–	–	yes
303-900	Lumen	GEORGETOWN	2007-01-10	yes	yes
303-901	T-Mobile	DENVER	–	yes	yes
303-902	Verizon	DENVER	–	–	yes
303-903	Verizon	DENVER	–	–	yes
303-904	Lumen	DENVER	–	–	yes
303-905	Verizon	DENVER	–	–	yes
303-906	Verizon	DENVER	–	–	yes
303-907	Verizon	DENVER	–	–	yes
303-908	Verizon	DENVER	–	–	yes
303-909	Verizon	DENVER	–	–	yes
303-910	Verizon	DENVER	–	–	yes
303-912	Verizon	DENVER	–	–	yes
303-913	Verizon	DENVER	–	–	yes
303-914	Lumen	DENVER	–	–	yes
303-915	Verizon	DENVER	–	–	yes
303-916	Verizon	DENVER	–	–	yes
303-917	Verizon	DENVER	–	yes	yes
303-918	Verizon	DENVER	–	–	yes
303-919	Verizon	DENVER	–	–	yes
303-920	Lumen	DENVER	–	–	yes
303-921	Verizon	DENVER	–	–	yes
303-922	Lumen	DENVER	–	–	yes
303-923	Lumen	DENVER	–	yes	yes
303-924	Lumen	DENVER	–	–	yes
303-925	Lumen	DENVER	–	–	yes
303-926	Lumen	DENVER	–	–	yes
303-927	AT&T	DENVER	–	yes	yes
303-928	Verizon	DENVER	–	yes	yes
303-929	Verizon	DENVER	–	–	yes
303-930	Lumen	DENVER	–	–	yes
303-931	T-Mobile	DENVER	–	–	yes
303-932	Lumen	DENVER	–	–	yes
303-933	Lumen	DENVER	–	–	yes
303-934	Lumen	DENVER	–	–	yes
303-935	Lumen	DENVER	–	–	yes
303-936	Lumen	DENVER	–	–	yes
303-937	Lumen	DENVER	–	–	yes
303-938	Lumen	DENVER	–	–	yes
303-939	Lumen	DENVER	–	–	yes
303-940	Lumen	DENVER	–	–	yes
303-941	Verizon	DENVER	–	–	yes
303-942	AT&T	DENVER	–	yes	yes
303-943	SKYE TELECOM LLC DBA SKYETEL	DENVER	2021-09-09	yes	yes
303-944	T-Mobile	DENVER	–	yes	yes
303-945	Comcast	DENVER	–	yes	yes
303-946	T-Mobile	DENVER	–	yes	yes
303-947	Verizon	DENVER	–	–	yes
303-948	Lumen	DENVER	–	–	yes
303-949	T-Mobile	DENVER	–	yes	yes
303-951	Lumen	DENVER	–	yes	yes
303-952	Lumen	DENVER	–	yes	yes
303-953	Lumen	DENVER	–	yes	yes
303-954	Lumen	DENVER	–	yes	yes
303-955	Lumen	DENVER	–	yes	yes
303-956	AT&T	FORTLUPTON	–	–	yes
303-957	Lumen	DENVER	–	yes	yes
303-960	T-Mobile	DENVER	–	–	yes
303-961	T-Mobile	DENVER	–	yes	yes
303-962	Onvoy	DENVER	–	yes	yes
303-963	Lumen	DENVER	–	yes	yes
303-964	Lumen	DENVER	–	–	yes
303-965	Lumen	DENVER	–	–	yes
303-966	Lumen	DENVER	–	–	yes
303-967	Lumen	DENVER	–	yes	yes
303-968	Verizon	DENVER	–	yes	yes
303-969	Lumen	DENVER	–	–	yes
303-970	Onvoy	DECKERS	2022-03-31	yes	yes
303-971	Lumen	DENVER	–	–	yes
303-972	Lumen	DENVER	–	–	yes
303-973	Lumen	DENVER	–	–	yes
303-974	Lumen	DENVER	–	yes	yes
303-975	Lumen	DENVER	–	yes	yes
303-977	Lumen	DENVER	–	–	yes
303-978	Lumen	DENVER	–	–	yes
303-979	Lumen	DENVER	–	–	yes
303-980	Lumen	DENVER	–	–	yes
303-981	Verizon	DENVER	–	–	yes
303-982	Lumen	DENVER	–	–	yes
303-984	Lumen	DENVER	–	–	yes
303-985	Lumen	DENVER	–	–	yes
303-986	Lumen	DENVER	–	–	yes
303-987	Lumen	DENVER	–	–	yes
303-988	Lumen	DENVER	–	–	yes
303-989	Lumen	DENVER	–	–	yes
303-990	T-Mobile	FORTLUPTON	2006-05-16	yes	yes
303-991	Verizon	DENVER	–	–	yes
303-992	Lumen	DENVER	–	–	yes
303-993	Onvoy	DENVER	2007-03-27	yes	yes
303-994	T-Mobile	DENVER	–	yes	yes
303-995	T-Mobile	DENVER	–	yes	yes
303-996	Allstream	DENVER	–	–	yes
303-997	Comcast	DENVER	–	yes	yes
303-998	Lumen	DENVER	–	–	yes
303-999	Comcast	DENVER	2007-08-24	yes	yes

Frequently asked

How many prefixes does area code 303 have?

784 NXX blocks are assigned of 786 possible. Each block is 10,000 consecutive numbers, so the code currently covers about 7,840 thousand-number ranges across 13 rate centers.

What do the first three digits after 303 tell me?

They identify the block, which tells you the rate center it was allocated to and the carrier that received it. They do not tell you who serves the number today: portability moves numbers between carriers, and pooling splits a block between several of them.

Is a 303 prefix tied to a specific town?

To a rate center, which is billing geography rather than a town. NANPA abbreviates rate center names to ten characters and in large metros uses zone codes, so the name is a NANPA label, not a place name.

What does “pooled” mean in the 303 table?

That the block is in thousands-block pooling: carriers draw 1,000-number lots from it instead of taking all 10,000. 228 of 303's blocks are pooled, which is how regulators slowed down area code exhaustion – and why one prefix can belong to several carriers.

Source and limits

NANPA CO Code Assignment Records, all states, utilized codes, file updated 11/01/2026 – the rows where the record's Use field is “AS” (assigned). Unavailable codes are excluded. The records say who received a block and when, not who serves a particular number today.

More about this code: overview · carriers · spam complaints · local time