Area Code 303
Area code 303 is in Colorado, USA , spanning 14 counties and serving 74 cities, including Denver, Aurora or Lakewood; it currently uses 784 prefixes, assigned from 303-200-XXXX through 303-999-XXXX.
In service since January 01, 1947, area code 303 is the parent Numbering Plan Area in overlay complex 303/720/983.
The current local time is .
For exact NPA boundaries see official 303 area code map
Phone number lookup
More Colorado area codes:
Locate any 303-NXX prefix:
| NPANXX | Area Served1 | Date1 |
|---|---|---|
| 303-200 | Denver | N/A |
| 303-201 | Denver | N/A |
| 303-202 | Denver | N/A |
| 303-203 | Denver | N/A |
| 303-204 | Denver | N/A |
| 303-205 | Denver | N/A |
| 303-206 | Denver | N/A |
| 303-207 | Denver | N/A |
| 303-208 | Denver | N/A |
| 303-209 | Denver | N/A |
| 303-210 | Denver | N/A |
| 303-212 | Denver | N/A |
| 303-213 | Denver | N/A |
| 303-214 | Denver | N/A |
| 303-215 | Denver | N/A |
| 303-216 | Denver | N/A |
| 303-217 | Denver | N/A |
| 303-218 | Denver | N/A |
| 303-219 | Denver | N/A |
| 303-220 | Denver | N/A |
| 303-221 | Denver | N/A |
| 303-222 | Denver | N/A |
| 303-223 | Denver | N/A |
| 303-224 | Denver | N/A |
| 303-225 | Denver | N/A |
| 303-226 | Denver | N/A |
| 303-227 | Denver | N/A |
| 303-228 | Denver | N/A |
| 303-229 | Denver | N/A |
| 303-230 | Denver | N/A |
| 303-231 | Denver | N/A |
| 303-232 | Denver | N/A |
| 303-233 | Denver | N/A |
| 303-234 | Denver | N/A |
| 303-235 | Denver | N/A |
| 303-236 | Denver | N/A |
| 303-237 | Denver | N/A |
| 303-238 | Denver | N/A |
| 303-239 | Denver | N/A |
| 303-240 | Denver | N/A |
| 303-241 | Denver | N/A |
| 303-242 | Denver | N/A |
| 303-243 | Denver | N/A |
| 303-244 | Denver | N/A |
| 303-245 | Denver | N/A |
| 303-246 | Denver | N/A |
| 303-247 | Denver | N/A |
| 303-248 | Denver | N/A |
| 303-249 | Denver | N/A |
| 303-250 | Denver | N/A |
| 303-251 | Denver | N/A |
| 303-252 | Denver | N/A |
| 303-253 | Denver | N/A |
| 303-254 | Denver | N/A |
| 303-255 | Denver | N/A |
| 303-256 | Denver | N/A |
| 303-257 | Denver | N/A |
| 303-258 | Denver | N/A |
| 303-259 | Denver | N/A |
| 303-260 | Denver | N/A |
| 303-261 | Denver | N/A |
| 303-262 | Denver | N/A |
| 303-263 | Denver | N/A |
| 303-264 | Denver | N/A |
| 303-265 | Denver | N/A |
| 303-266 | Denver | N/A |
| 303-267 | Denver | N/A |
| 303-268 | Denver | N/A |
| 303-269 | Denver | N/A |
| 303-270 | Denver | N/A |
| 303-271 | Denver | N/A |
| 303-272 | Denver | N/A |
| 303-273 | Denver | N/A |
| 303-274 | Denver | N/A |
| 303-275 | Denver | N/A |
| 303-276 | Denver | 8/19/2021 |
| 303-277 | Denver | N/A |
| 303-278 | Denver | N/A |
| 303-279 | Denver | N/A |
| 303-280 | Denver | N/A |
| 303-281 | Denver | N/A |
| 303-282 | Denver | N/A |
| 303-283 | Denver | N/A |
| 303-284 | Denver | N/A |
| 303-285 | Denver | N/A |
| 303-286 | Denver | N/A |
| 303-287 | Denver | N/A |
| 303-288 | Denver | N/A |
| 303-289 | Denver | N/A |
| 303-290 | Denver | N/A |
| 303-291 | Denver | N/A |
| 303-292 | Denver | N/A |
| 303-293 | Denver | N/A |
| 303-294 | Denver | N/A |
| 303-295 | Denver | N/A |
| 303-296 | Denver | N/A |
| 303-297 | Denver | N/A |
| 303-298 | Denver | N/A |
| 303-299 | Denver | N/A |
| NPANXX | Area Served1 | Date1 |
|---|---|---|
| 303-300 | Denver | N/A |
| 303-301 | Denver | N/A |
| 303-302 | Denver | N/A |
| 303-303 | Denver | 08/26/2024 |
| 303-304 | Fort Lupton | 11/18/2004 |
| 303-305 | Denver | N/A |
| 303-306 | Denver | N/A |
| 303-307 | Denver | N/A |
| 303-308 | Denver | N/A |
| 303-309 | Denver | N/A |
| 303-310 | Denver | N/A |
| 303-312 | Denver | N/A |
| 303-313 | Denver | N/A |
| 303-314 | Denver | N/A |
| 303-315 | Denver | N/A |
| 303-316 | Denver | N/A |
| 303-317 | Denver | N/A |
| 303-318 | Denver | N/A |
| 303-319 | Denver | 8/12/2004 |
| 303-320 | Denver | N/A |
| 303-321 | Denver | N/A |
| 303-322 | Denver | N/A |
| 303-323 | Denver | N/A |
| 303-324 | Denver | N/A |
| 303-325 | Denver | N/A |
| 303-326 | Denver | N/A |
| 303-327 | Denver | N/A |
| 303-328 | Denver | N/A |
| 303-329 | Denver | N/A |
| 303-330 | Denver | 3/9/2006 |
| 303-331 | Denver | N/A |
| 303-332 | Denver | N/A |
| 303-333 | Denver | N/A |
| 303-334 | Denver | N/A |
| 303-335 | Denver | N/A |
| 303-336 | Denver | N/A |
| 303-337 | Denver | N/A |
| 303-338 | Denver | N/A |
| 303-339 | Denver | 12/15/2003 |
| 303-340 | Denver | N/A |
| 303-341 | Denver | N/A |
| 303-342 | Denver | N/A |
| 303-343 | Denver | N/A |
| 303-344 | Denver | N/A |
| 303-345 | Denver | N/A |
| 303-346 | Denver | N/A |
| 303-347 | Denver | N/A |
| 303-348 | Denver | N/A |
| 303-349 | Denver | N/A |
| 303-350 | Denver | N/A |
| 303-351 | Deckers | 11/8/2006 |
| 303-352 | Denver | N/A |
| 303-353 | Denver | N/A |
| 303-354 | Denver | N/A |
| 303-355 | Denver | N/A |
| 303-356 | Denver | N/A |
| 303-357 | Denver | N/A |
| 303-358 | Denver | N/A |
| 303-359 | Denver | N/A |
| 303-360 | Denver | N/A |
| 303-361 | Denver | N/A |
| 303-362 | Denver | N/A |
| 303-363 | Denver | N/A |
| 303-364 | Denver | N/A |
| 303-365 | Denver | N/A |
| 303-366 | Denver | N/A |
| 303-367 | Denver | N/A |
| 303-368 | Denver | N/A |
| 303-369 | Denver | N/A |
| 303-370 | Denver | N/A |
| 303-371 | Denver | N/A |
| 303-372 | Denver | N/A |
| 303-373 | Denver | N/A |
| 303-374 | Denver | N/A |
| 303-375 | Denver | N/A |
| 303-376 | Denver | N/A |
| 303-377 | Denver | N/A |
| 303-378 | Denver | N/A |
| 303-379 | Denver | N/A |
| 303-380 | Denver | N/A |
| 303-381 | Denver | N/A |
| 303-382 | Denver | N/A |
| 303-383 | Denver | N/A |
| 303-384 | Denver | N/A |
| 303-385 | Denver | N/A |
| 303-386 | Denver | N/A |
| 303-387 | Denver | N/A |
| 303-388 | Denver | N/A |
| 303-389 | Denver | N/A |
| 303-390 | Denver | N/A |
| 303-391 | Denver | N/A |
| 303-392 | Denver | 01/16/2025 |
| 303-393 | Denver | N/A |
| 303-394 | Denver | N/A |
| 303-395 | Denver | N/A |
| 303-396 | Denver | 6/1/2005 |
| 303-397 | Denver | N/A |
| 303-398 | Denver | N/A |
| 303-399 | Denver | N/A |
| NPANXX | Area Served1 | Date1 |
|---|---|---|
| 303-400 | Denver | N/A |
| 303-401 | Denver | N/A |
| 303-402 | Denver | N/A |
| 303-403 | Denver | N/A |
| 303-404 | Denver | N/A |
| 303-405 | Denver | N/A |
| 303-406 | Denver | N/A |
| 303-407 | Denver | N/A |
| 303-408 | Denver | N/A |
| 303-409 | Denver | N/A |
| 303-410 | Denver | N/A |
| 303-412 | Denver | N/A |
| 303-413 | Denver | N/A |
| 303-414 | Denver | N/A |
| 303-415 | Denver | N/A |
| 303-416 | Denver | N/A |
| 303-417 | Denver | N/A |
| 303-418 | Denver | N/A |
| 303-419 | Denver | N/A |
| 303-420 | Denver | N/A |
| 303-421 | Denver | N/A |
| 303-422 | Denver | N/A |
| 303-423 | Denver | N/A |
| 303-424 | Denver | N/A |
| 303-425 | Denver | N/A |
| 303-426 | Denver | N/A |
| 303-427 | Denver | N/A |
| 303-428 | Denver | N/A |
| 303-429 | Denver | N/A |
| 303-430 | Denver | N/A |
| 303-431 | Denver | N/A |
| 303-432 | Denver | N/A |
| 303-433 | Denver | N/A |
| 303-434 | Denver | N/A |
| 303-435 | Denver | N/A |
| 303-436 | Denver | N/A |
| 303-437 | Denver | N/A |
| 303-438 | Denver | N/A |
| 303-439 | Denver | N/A |
| 303-440 | Denver | N/A |
| 303-441 | Denver | N/A |
| 303-442 | Denver | N/A |
| 303-443 | Denver | N/A |
| 303-444 | Denver | N/A |
| 303-445 | Denver | N/A |
| 303-446 | Denver | N/A |
| 303-447 | Denver | N/A |
| 303-448 | Denver | N/A |
| 303-449 | Denver | N/A |
| 303-450 | Denver | N/A |
| 303-451 | Denver | N/A |
| 303-452 | Denver | N/A |
| 303-453 | Denver | N/A |
| 303-454 | Denver | N/A |
| 303-455 | Denver | N/A |
| 303-456 | Denver | N/A |
| 303-457 | Denver | N/A |
| 303-458 | Denver | N/A |
| 303-459 | Denver | N/A |
| 303-460 | Denver | N/A |
| 303-461 | Denver | N/A |
| 303-462 | Denver | N/A |
| 303-463 | Denver | N/A |
| 303-464 | Denver | N/A |
| 303-465 | Denver | N/A |
| 303-466 | Denver | N/A |
| 303-467 | Denver | N/A |
| 303-468 | Denver | 5/24/2001 |
| 303-469 | Denver | N/A |
| 303-470 | Denver | N/A |
| 303-471 | Denver | N/A |
| 303-472 | Denver | N/A |
| 303-473 | Denver | N/A |
| 303-474 | Denver | N/A |
| 303-475 | Denver | N/A |
| 303-476 | Denver | N/A |
| 303-477 | Denver | N/A |
| 303-478 | Denver | N/A |
| 303-479 | Denver | N/A |
| 303-480 | Denver | N/A |
| 303-481 | Denver | N/A |
| 303-482 | Denver | N/A |
| 303-483 | Denver | N/A |
| 303-484 | Denver | N/A |
| 303-485 | Longmont | N/A |
| 303-486 | Denver | N/A |
| 303-487 | Denver | N/A |
| 303-488 | Denver | N/A |
| 303-489 | Denver | N/A |
| 303-490 | Denver | N/A |
| 303-491 | Denver | N/A |
| 303-492 | Denver | N/A |
| 303-493 | Denver | N/A |
| 303-494 | Denver | N/A |
| 303-495 | Denver | N/A |
| 303-496 | Denver | 4/8/2004 |
| 303-497 | Denver | N/A |
| 303-498 | Denver | 4/22/2005 |
| 303-499 | Denver | N/A |
| NPANXX | Area Served1 | Date1 |
|---|---|---|
| 303-500 | Hudson | 1/4/2005 |
| 303-501 | Denver | 1/26/2006 |
| 303-502 | Fort Lupton | 12/13/2005 |
| 303-503 | Denver | N/A |
| 303-504 | Denver | N/A |
| 303-505 | Denver | 11/9/2012 |
| 303-506 | Fort Lupton | 9/13/2001 |
| 303-507 | Denver | N/A |
| 303-508 | Denver | N/A |
| 303-509 | Denver | N/A |
| 303-510 | Denver | N/A |
| 303-512 | Denver | N/A |
| 303-513 | Denver | 2/15/2002 |
| 303-514 | Denver | N/A |
| 303-515 | Denver | 11/14/2011 |
| 303-516 | Denver | N/A |
| 303-517 | Denver | N/A |
| 303-518 | Denver | N/A |
| 303-519 | Denver | N/A |
| 303-520 | Denver | N/A |
| 303-521 | Denver | N/A |
| 303-522 | Denver | N/A |
| 303-523 | Denver | N/A |
| 303-524 | Denver | N/A |
| 303-525 | Denver | N/A |
| 303-526 | Denver | N/A |
| 303-527 | Denver | N/A |
| 303-528 | Denver | N/A |
| 303-529 | Denver | 10/7/2019 |
| 303-530 | Denver | N/A |
| 303-531 | Denver | N/A |
| 303-532 | Longmont | N/A |
| 303-533 | Denver | N/A |
| 303-534 | Denver | N/A |
| 303-535 | Fort Lupton | N/A |
| 303-536 | Hudson | N/A |
| 303-537 | Denver | N/A |
| 303-538 | Denver | N/A |
| 303-539 | Denver | N/A |
| 303-540 | Denver | N/A |
| 303-541 | Denver | N/A |
| 303-542 | Denver | N/A |
| 303-543 | Denver | N/A |
| 303-544 | Denver | N/A |
| 303-545 | Denver | N/A |
| 303-546 | Denver | N/A |
| 303-547 | Denver | N/A |
| 303-548 | Denver | N/A |
| 303-549 | Denver | N/A |
| 303-550 | Denver | N/A |
| 303-551 | Denver | N/A |
| 303-552 | Denver | N/A |
| 303-553 | Denver | N/A |
| 303-554 | Denver | N/A |
| 303-556 | Denver | N/A |
| 303-557 | Denver | N/A |
| 303-558 | Denver | N/A |
| 303-559 | Denver | N/A |
| 303-560 | Denver | N/A |
| 303-561 | Denver | N/A |
| 303-562 | Denver | N/A |
| 303-563 | Denver | N/A |
| 303-564 | Denver | N/A |
| 303-565 | Denver | N/A |
| 303-566 | Denver | N/A |
| 303-567 | Denver | N/A |
| 303-568 | Denver | N/A |
| 303-569 | Georgetown | N/A |
| 303-570 | Denver | N/A |
| 303-571 | Denver | N/A |
| 303-572 | Denver | N/A |
| 303-573 | Denver | N/A |
| 303-574 | Denver | N/A |
| 303-575 | Denver | N/A |
| 303-576 | Denver | N/A |
| 303-577 | Denver | N/A |
| 303-578 | Keenesburg | 9/12/2006 |
| 303-579 | Denver | N/A |
| 303-580 | Denver | N/A |
| 303-581 | Denver | N/A |
| 303-582 | Denver | N/A |
| 303-583 | Denver | N/A |
| 303-584 | Denver | N/A |
| 303-585 | Denver | N/A |
| 303-586 | Denver | N/A |
| 303-587 | Denver | N/A |
| 303-588 | Denver | N/A |
| 303-589 | Denver | N/A |
| 303-590 | Denver | N/A |
| 303-591 | Denver | N/A |
| 303-592 | Denver | N/A |
| 303-593 | Denver | N/A |
| 303-594 | Denver | N/A |
| 303-595 | Denver | N/A |
| 303-596 | Denver | N/A |
| 303-597 | Denver | N/A |
| 303-598 | Denver | N/A |
| 303-599 | Denver | N/A |
| NPANXX | Area Served1 | Date1 |
|---|---|---|
| 303-600 | Denver | N/A |
| 303-601 | Denver | N/A |
| 303-602 | Denver | N/A |
| 303-603 | Denver | N/A |
| 303-604 | Denver | N/A |
| 303-605 | Denver | N/A |
| 303-606 | Denver | N/A |
| 303-607 | Denver | N/A |
| 303-608 | Denver | N/A |
| 303-609 | Denver | N/A |
| 303-610 | Denver | N/A |
| 303-612 | Denver | N/A |
| 303-613 | Denver | N/A |
| 303-614 | Denver | N/A |
| 303-615 | Denver | N/A |
| 303-616 | Denver | N/A |
| 303-617 | Denver | N/A |
| 303-618 | Denver | N/A |
| 303-619 | Denver | N/A |
| 303-620 | Denver | N/A |
| 303-621 | Denver | N/A |
| 303-622 | Strasburg | N/A |
| 303-623 | Denver | N/A |
| 303-624 | Denver | N/A |
| 303-625 | Denver | N/A |
| 303-626 | Denver | N/A |
| 303-627 | Denver | N/A |
| 303-628 | Denver | N/A |
| 303-629 | Denver | N/A |
| 303-630 | Denver | N/A |
| 303-632 | Denver | N/A |
| 303-633 | Denver | N/A |
| 303-634 | Denver | N/A |
| 303-635 | Denver | N/A |
| 303-636 | Denver | N/A |
| 303-637 | Denver | N/A |
| 303-638 | Denver | N/A |
| 303-639 | Denver | N/A |
| 303-640 | Denver | N/A |
| 303-641 | Denver | N/A |
| 303-642 | Denver | N/A |
| 303-643 | Denver | N/A |
| 303-644 | Bennett | N/A |
| 303-645 | Denver | N/A |
| 303-646 | Denver | N/A |
| 303-647 | Deckers | N/A |
| 303-648 | Denver | N/A |
| 303-649 | Denver | N/A |
| 303-650 | Denver | N/A |
| 303-651 | Longmont | N/A |
| 303-652 | Longmont | N/A |
| 303-653 | Denver | N/A |
| 303-654 | Denver | N/A |
| 303-655 | Denver | N/A |
| 303-656 | Denver | N/A |
| 303-657 | Denver | N/A |
| 303-658 | Denver | N/A |
| 303-659 | Denver | N/A |
| 303-660 | Denver | N/A |
| 303-661 | Denver | N/A |
| 303-662 | Denver | N/A |
| 303-663 | Denver | N/A |
| 303-664 | Denver | N/A |
| 303-665 | Denver | N/A |
| 303-666 | Denver | N/A |
| 303-667 | Denver | N/A |
| 303-668 | Denver | N/A |
| 303-669 | Denver | N/A |
| 303-670 | Denver | N/A |
| 303-671 | Denver | N/A |
| 303-672 | Denver | N/A |
| 303-673 | Denver | N/A |
| 303-674 | Denver | N/A |
| 303-675 | Denver | N/A |
| 303-676 | Denver | N/A |
| 303-677 | Denver | N/A |
| 303-678 | Longmont | N/A |
| 303-679 | Denver | N/A |
| 303-680 | Denver | N/A |
| 303-681 | Denver | N/A |
| 303-682 | Longmont | N/A |
| 303-683 | Denver | N/A |
| 303-684 | Longmont | N/A |
| 303-685 | Denver | N/A |
| 303-686 | Denver | N/A |
| 303-687 | Denver | N/A |
| 303-688 | Denver | N/A |
| 303-689 | Denver | N/A |
| 303-690 | Denver | N/A |
| 303-691 | Denver | N/A |
| 303-692 | Denver | N/A |
| 303-693 | Denver | N/A |
| 303-694 | Denver | N/A |
| 303-695 | Denver | N/A |
| 303-696 | Denver | N/A |
| 303-697 | Denver | N/A |
| 303-698 | Denver | N/A |
| 303-699 | Denver | N/A |
| NPANXX | Area Served1 | Date1 |
|---|---|---|
| 303-701 | Denver | N/A |
| 303-702 | Longmont | N/A |
| 303-703 | Denver | N/A |
| 303-704 | Denver | N/A |
| 303-705 | Denver | N/A |
| 303-706 | Denver | N/A |
| 303-707 | Denver | N/A |
| 303-708 | Denver | N/A |
| 303-709 | Longmont | N/A |
| 303-710 | Fort Lupton | N/A |
| 303-712 | Denver | N/A |
| 303-713 | Denver | N/A |
| 303-714 | Denver | N/A |
| 303-715 | Denver | N/A |
| 303-716 | Denver | N/A |
| 303-717 | Fort Lupton | N/A |
| 303-718 | Fort Lupton | N/A |
| 303-719 | Deer Trail | 11/16/2006 |
| 303-720 | Fort Lupton | 6/13/2008 |
| 303-721 | Denver | N/A |
| 303-722 | Denver | N/A |
| 303-723 | Denver | N/A |
| 303-724 | Denver | N/A |
| 303-725 | Denver | N/A |
| 303-726 | Denver | N/A |
| 303-727 | Denver | N/A |
| 303-728 | Denver | N/A |
| 303-729 | Denver | N/A |
| 303-730 | Denver | N/A |
| 303-731 | Denver | N/A |
| 303-732 | Keenesburg | N/A |
| 303-733 | Denver | N/A |
| 303-734 | Denver | N/A |
| 303-735 | Denver | N/A |
| 303-736 | Denver | N/A |
| 303-737 | Denver | N/A |
| 303-738 | Denver | N/A |
| 303-739 | Denver | N/A |
| 303-740 | Denver | N/A |
| 303-741 | Denver | N/A |
| 303-742 | Denver | N/A |
| 303-743 | Denver | N/A |
| 303-744 | Denver | N/A |
| 303-745 | Denver | N/A |
| 303-746 | Longmont | N/A |
| 303-747 | Allenspark/ Lyons | N/A |
| 303-748 | Denver | N/A |
| 303-749 | Denver | N/A |
| 303-750 | Denver | N/A |
| 303-751 | Denver | N/A |
| 303-752 | Denver | N/A |
| 303-753 | Denver | N/A |
| 303-754 | Denver | N/A |
| 303-755 | Denver | N/A |
| 303-756 | Denver | N/A |
| 303-757 | Denver | N/A |
| 303-758 | Denver | N/A |
| 303-759 | Denver | N/A |
| 303-760 | Denver | N/A |
| 303-761 | Denver | N/A |
| 303-762 | Denver | N/A |
| 303-763 | Denver | N/A |
| 303-764 | Denver | N/A |
| 303-765 | Denver | N/A |
| 303-766 | Denver | N/A |
| 303-767 | Denver | N/A |
| 303-768 | Denver | N/A |
| 303-769 | Deer Trail | N/A |
| 303-770 | Denver | N/A |
| 303-771 | Denver | N/A |
| 303-772 | Longmont | N/A |
| 303-773 | Denver | N/A |
| 303-774 | Longmont | N/A |
| 303-775 | Longmont | N/A |
| 303-776 | Longmont | N/A |
| 303-777 | Denver | N/A |
| 303-778 | Denver | N/A |
| 303-779 | Denver | N/A |
| 303-780 | Denver | N/A |
| 303-781 | Denver | N/A |
| 303-782 | Denver | N/A |
| 303-783 | Denver | N/A |
| 303-784 | Denver | N/A |
| 303-785 | Denver | N/A |
| 303-786 | Denver | N/A |
| 303-787 | Denver | N/A |
| 303-788 | Denver | N/A |
| 303-789 | Denver | N/A |
| 303-790 | Denver | N/A |
| 303-791 | Denver | N/A |
| 303-792 | Denver | N/A |
| 303-793 | Denver | N/A |
| 303-794 | Denver | N/A |
| 303-795 | Denver | N/A |
| 303-796 | Denver | N/A |
| 303-797 | Denver | N/A |
| 303-798 | Denver | N/A |
| 303-799 | Denver | N/A |
| NPANXX | Area Served1 | Date1 |
|---|---|---|
| 303-800 | Denver | N/A |
| 303-801 | Denver | N/A |
| 303-802 | Denver | N/A |
| 303-803 | Denver | N/A |
| 303-804 | Denver | N/A |
| 303-805 | Denver | N/A |
| 303-806 | Denver | N/A |
| 303-807 | Denver | N/A |
| 303-808 | Denver | N/A |
| 303-809 | Denver | N/A |
| 303-810 | Denver | N/A |
| 303-812 | Denver | N/A |
| 303-813 | Denver | N/A |
| 303-814 | Denver | N/A |
| 303-815 | Denver | 2/3/2005 |
| 303-816 | Deckers | N/A |
| 303-817 | Denver | N/A |
| 303-818 | Denver | N/A |
| 303-819 | Denver | N/A |
| 303-820 | Denver | N/A |
| 303-821 | Denver | N/A |
| 303-822 | Byers | N/A |
| 303-823 | Allenspark/ Lyons | N/A |
| 303-824 | Denver | N/A |
| 303-825 | Denver | N/A |
| 303-826 | Denver | N/A |
| 303-827 | Longmont | N/A |
| 303-828 | Denver | N/A |
| 303-829 | Denver | N/A |
| 303-830 | Denver | N/A |
| 303-831 | Denver | N/A |
| 303-832 | Denver | N/A |
| 303-833 | Denver | N/A |
| 303-834 | Longmont | 9/27/2006 |
| 303-835 | Denver | N/A |
| 303-836 | Denver | N/A |
| 303-837 | Denver | N/A |
| 303-838 | Deckers | N/A |
| 303-839 | Denver | N/A |
| 303-840 | Denver | N/A |
| 303-841 | Denver | N/A |
| 303-842 | Denver | N/A |
| 303-843 | Denver | N/A |
| 303-844 | Denver | N/A |
| 303-845 | Longmont | N/A |
| 303-846 | Denver | N/A |
| 303-847 | Denver | N/A |
| 303-848 | Longmont | N/A |
| 303-849 | Roggen | N/A |
| 303-850 | Denver | N/A |
| 303-851 | Denver | N/A |
| 303-852 | Denver | N/A |
| 303-853 | Denver | N/A |
| 303-854 | Denver | N/A |
| 303-855 | Denver | N/A |
| 303-856 | Denver | N/A |
| 303-857 | Fort Lupton | N/A |
| 303-858 | Denver | N/A |
| 303-859 | Denver | N/A |
| 303-860 | Denver | N/A |
| 303-861 | Denver | N/A |
| 303-862 | Denver | 6/4/2005 |
| 303-863 | Denver | N/A |
| 303-864 | Denver | N/A |
| 303-865 | Denver | N/A |
| 303-866 | Denver | N/A |
| 303-867 | Denver | 11/4/2005 |
| 303-868 | Denver | N/A |
| 303-869 | Denver | N/A |
| 303-870 | Denver | N/A |
| 303-871 | Denver | N/A |
| 303-872 | Denver | N/A |
| 303-873 | Denver | N/A |
| 303-874 | Denver | N/A |
| 303-875 | Denver | N/A |
| 303-876 | Denver | N/A |
| 303-877 | Denver | N/A |
| 303-878 | Denver | N/A |
| 303-879 | Denver | N/A |
| 303-880 | Denver | N/A |
| 303-881 | Denver | N/A |
| 303-882 | Denver | N/A |
| 303-883 | Denver | N/A |
| 303-884 | Denver | N/A |
| 303-885 | Denver | 4/12/2001 |
| 303-886 | Denver | 4/12/2001 |
| 303-887 | Denver | 4/12/2001 |
| 303-888 | Denver | N/A |
| 303-889 | Denver | N/A |
| 303-890 | Denver | N/A |
| 303-891 | Denver | N/A |
| 303-892 | Denver | N/A |
| 303-893 | Denver | N/A |
| 303-894 | Denver | N/A |
| 303-895 | Denver | N/A |
| 303-896 | Denver | N/A |
| 303-897 | Denver | N/A |
| 303-898 | Denver | N/A |
| 303-899 | Denver | N/A |
| NPANXX | Area Served1 | Date1 |
|---|---|---|
| 303-900 | Georgetown | 1/10/2007 |
| 303-901 | Denver | N/A |
| 303-902 | Denver | N/A |
| 303-903 | Denver | N/A |
| 303-904 | Denver | N/A |
| 303-905 | Denver | N/A |
| 303-906 | Denver | N/A |
| 303-907 | Denver | N/A |
| 303-908 | Denver | N/A |
| 303-909 | Denver | N/A |
| 303-910 | Denver | N/A |
| 303-912 | Denver | N/A |
| 303-913 | Denver | N/A |
| 303-914 | Denver | N/A |
| 303-915 | Denver | N/A |
| 303-916 | Denver | N/A |
| 303-917 | Denver | N/A |
| 303-918 | Denver | N/A |
| 303-919 | Denver | N/A |
| 303-920 | Denver | N/A |
| 303-921 | Denver | N/A |
| 303-922 | Denver | N/A |
| 303-923 | Denver | N/A |
| 303-924 | Denver | N/A |
| 303-925 | Denver | N/A |
| 303-926 | Denver | N/A |
| 303-927 | Denver | N/A |
| 303-928 | Denver | N/A |
| 303-929 | Denver | N/A |
| 303-930 | Denver | N/A |
| 303-931 | Denver | N/A |
| 303-932 | Denver | N/A |
| 303-933 | Denver | N/A |
| 303-934 | Denver | N/A |
| 303-935 | Denver | N/A |
| 303-936 | Denver | N/A |
| 303-937 | Denver | N/A |
| 303-938 | Denver | N/A |
| 303-939 | Denver | N/A |
| 303-940 | Denver | N/A |
| 303-941 | Denver | N/A |
| 303-942 | Denver | N/A |
| 303-943 | Denver | 9/9/2021 |
| 303-944 | Denver | N/A |
| 303-945 | Denver | N/A |
| 303-946 | Denver | N/A |
| 303-947 | Denver | N/A |
| 303-948 | Denver | N/A |
| 303-949 | Denver | N/A |
| 303-951 | Denver | N/A |
| 303-952 | Denver | N/A |
| 303-953 | Denver | N/A |
| 303-954 | Denver | N/A |
| 303-955 | Denver | N/A |
| 303-956 | Fort Lupton | N/A |
| 303-957 | Denver | N/A |
| 303-960 | Denver | N/A |
| 303-961 | Denver | N/A |
| 303-962 | Denver | 7/14/2005 |
| 303-963 | Denver | N/A |
| 303-964 | Denver | N/A |
| 303-965 | Denver | N/A |
| 303-966 | Denver | N/A |
| 303-967 | Denver | N/A |
| 303-968 | Denver | N/A |
| 303-969 | Denver | N/A |
| 303-970 | Deckers | 3/31/2022 |
| 303-971 | Denver | N/A |
| 303-972 | Denver | N/A |
| 303-973 | Denver | N/A |
| 303-974 | Denver | N/A |
| 303-975 | Denver | N/A |
| 303-977 | Denver | N/A |
| 303-978 | Denver | N/A |
| 303-979 | Denver | N/A |
| 303-980 | Denver | N/A |
| 303-981 | Denver | N/A |
| 303-982 | Denver | N/A |
| 303-984 | Denver | N/A |
| 303-985 | Denver | N/A |
| 303-986 | Denver | N/A |
| 303-987 | Denver | N/A |
| 303-988 | Denver | N/A |
| 303-989 | Denver | N/A |
| 303-990 | Fort Lupton | 5/16/2006 |
| 303-991 | Denver | N/A |
| 303-992 | Denver | N/A |
| 303-993 | Denver | 3/27/2007 |
| 303-994 | Denver | N/A |
| 303-995 | Denver | N/A |
| 303-996 | Denver | N/A |
| 303-997 | Denver | N/A |
| 303-998 | Denver | N/A |
| 303-999 | Denver | 8/24/2007 |
- For 'Area served' we list the rate center. In the North American Numbering Plan a rate center is a geographic area used to determine local calling boundaries for billing purposes. Its name is generally a locality, often not the only one served by an NPA-NXX combination.
- Assignment date. N/A - mostly central office codes assigned before 2001.
- NXX prefixes last updated: June 3, 2025
Cities in area code 303
| City1 | County | Time Zone1 |
|---|---|---|
| Allenspark | Boulder | M |
| Arvada | Jefferson | M |
| Aurora | Adams | M |
| Bailey | Park | M |
| Bennett | Adams | M |
| Black Hawk | Gilpin | M |
| Bond | Eagle | M |
| Boulder | Boulder | M |
| Brighton | Adams | M |
| Broomfield | Broomfield | M |
| Buffalo Creek | Jefferson | M |
| Byers | Arapahoe | M |
| Castle Rock | Douglas | M |
| Central City | Gilpin | M |
| Commerce City | Adams | M |
| Conifer | Jefferson | M |
| Dacono | Weld | M |
| Deer Trail | Arapahoe | M |
| Denver | Adams | M |
| Dumont | Clear Creek | M |
| Dupont | Adams | M |
| Eastlake | Adams | M |
| Elbert | El Paso | M |
| Eldorado Springs | Boulder | M |
| Elizabeth | Elbert | M |
| Empire | Clear Creek | M |
| Englewood | Arapahoe | M |
| Erie | Weld | M |
| Evergreen | Jefferson | M |
| Firestone | Weld | M |
| Fort Lupton | Weld | M |
| Franktown | Douglas | M |
| Frederick | Weld | M |
| Georgetown | Clear Creek | M |
| Golden | Jefferson | M |
| Grant | Park | M |
| Henderson | Adams | M |
| Hereford | Weld | M |
| Highlands Ranch | Douglas | M |
| Hudson | Weld | M |
| Hygiene | Boulder | M |
| Idaho Springs | Clear Creek | M |
| Idledale | Jefferson | M |
| Indian Hills | Jefferson | M |
| Jamestown | Boulder | M |
| Keenesburg | Weld | M |
| Kiowa | Elbert | M |
| Kittredge | Jefferson | M |
| Lafayette | Boulder | M |
| Lakewood | Jefferson | M |
| Larkspur | Douglas | M |
| Littleton | Arapahoe | M |
| Longmont | Boulder | M |
| Louisville | Boulder | M |
| Louviers | Douglas | M |
| Lyons | Boulder | M |
| Morrison | Jefferson | M |
| Nederland | Boulder | M |
| Niwot | Boulder | M |
| Parker | Douglas | M |
| Pine | Jefferson | M |
| Pinecliffe | Boulder | M |
| Roggen | Weld | M |
| Rollinsville | Gilpin | M |
| Sedalia | Douglas | M |
| Sedgwick | Sedgwick | M |
| Shawnee | Park | M |
| Silver Plume | Clear Creek | M |
| Strasburg | Adams | M |
| Thornton | Adams | M |
| Ward | Boulder | M |
| Watkins | Adams | M |
| Westminster | Adams | M |
| Wheat Ridge | Jefferson | M |
- Listed above are most places served by USA area code 303. When multiple places in a US state share the same name we list the largest one only. Cities with population over 50,000 are displayed in bold text.
- M stands for Mountain Time (currently ).