| 0000 | Reserved for Testing Purposes Only | | | USA |
| 0023 | Reynwood Communications of NY/NJ, LLC | Tinton Falls | NJ | USA |
| 0062 | Ropir Industries, Inc. dba Ropir Communications | Montgomery | AL | USA |
| 0247 | Rogers Cable Communications Inc. | Toronto | ON | CANADA |
| 0336 | RCN Long Distance Company | Wilkes-Barre | PA | USA |
| 0348 | Rogers Telecom Inc. | North York | ON | CANADA |
| 0411 | RESTRICTED-Unavailable for assignment until further notice | | | USA |
| 0463 | Redwood Long Distance | Wabasso | MN | USA |
| 0519 | RSL COM U.S.A. | --- | -- | USA |
| 0587 | Rystec Inc. | Branson | MO | USA |
| 0624 | Ripple Services, Inc. | Incline Village | NV | USA |
| 0677 | Reduced Rate Long Distance, LLC | Orlando | FL | USA |
| 0773 | Rogers Telecom Inc. | North York | ON | CANADA |
| 0946 | RSL COM U.S.A., Inc. | --- | -- | USA |
| 1411 | RESTRICTED-Unavailable for assignment until further notice | | | USA |
| 1633 | Red River Rural Telephone Association, Inc. | Abercrombie | ND | USA |
| 2411 | RESTRICTED-Unavailable for assignment until further notice | | | USA |
| 3411 | RESTRICTED-Unavailable for assignment until further notice | | | USA |
| 4110 | RESTRICTED-Unavailable for assignment until further notice | | | USA |
| 4111 | RESTRICTED-Unavailable for assignment until further notice | | | USA |
| 4112 | RESTRICTED-Unavailable for assignment until further notice | | | USA |
| 4113 | RESTRICTED-Unavailable for assignment until further notice | | | USA |
| 4114 | RESTRICTED-Unavailable for assignment until further notice | | | USA |
| 4115 | RESTRICTED-Unavailable for assignment until further notice | | | USA |
| 4116 | RESTRICTED-Unavailable for assignment until further notice | | | USA |
| 4117 | RESTRICTED-Unavailable for assignment until further notice | | | USA |
| 4118 | RESTRICTED-Unavailable for assignment until further notice | | | USA |
| 4119 | RESTRICTED-Unavailable for assignment until further notice | | | USA |
| 4411 | RESTRICTED-Unavailable for assignment until further notice | | | USA |
| 4746 | Rio Communications, Inc. | Bend | OR | USA |
| 5000 | Reserved for Testing Purposes Only | | | USA |
| 5022 | Race Telecommunications, Inc. | South San Francisco | CA | USA |
| 5033 | Rea Long Distance | Dallas | TX | USA |
| 5092 | RTC Communications Corp. dba RTC Long Distance | Rochester | IN | USA |
| 5103 | Reserve Long Distance t/a Reserve Telecommunications | Reserve | LA | USA |
| 5113 | RCN Telecom Services, Inc. | Wilkes-Barr | PA | USA |
| 5220 | Reach Direct | Dallas | TX | USA |
| 5236 | Roxborough Telephone Company Limited | Moose Creek | ON | CANADA |
| 5411 | RESTRICTED-Unavailable for assignment until further notice | | | USA |
| 5421 | Ruddata Corp. dba Vision Communications | Paducah | KY | USA |
| 5543 | RNK, Inc. | Dedham | MA | USA |
| 5643 | Royale Comtronics, Inc. | Perham | MN | USA |
| 5672 | RSL COM U.S.A., Inc. | --- | -- | USA |
| 5691 | Reynolds Long Distance, Inc. | Reynolds | IL | USA |
| 5721 | R&B Network, Inc. (wholly owned sub. of NTELOS Inc.) | Waynesboro | VA | USA |
| 5750 | Runestone Telephone Association | Hoffman | MN | USA |
| 5764 | Roanoke Telephone Co. | Monroe | LA | USA |
| 5794 | Randolph Telephone Telecommunications, Inc. | Asheboro | NC | USA |
| 5795 | Randolph Telephone Telecommunications, Inc. | Asheboro | NC | USA |
| 5832 | Rainier Connect, Inc. | Centralia | WA | USA |
| 5870 | Ringgold Telephone Long Distance | Ringgold | GA | USA |
| 5874 | RTC Solutions, Inc. | Ringgold | GA | USA |
| 5940 | Republican National Telephone Company | Dallas | TX | USA |
| 5950 | Rock Port Telephone Company | Rock Port | MO | USA |
| 5972 | Rogers Telecom Inc. | North York | ON | CANADA |
| 5984 | Reedsburg Utility Commission | Reedsburg | WI | USA |
| 6024 | Richmond Connections, Inc. | Richmond | MA | USA |
| 6045 | Rainbow Telecommunications Association, Inc. | Everest | KS | USA |
| 6156 | Rice Belt Telephone Co., Inc. | Weiner | AR | USA |
| 6411 | RESTRICTED-Unavailable for assignment until further notice | | | USA |
| 6621 | RCN Telecom Services of Illinois Inc. | Wilkes-Barre | PA | USA |
| 6669 | Richland-Grant Long Distance, Inc. | Blue River | WI | USA |
| 6784 | RTI Communications | Los Angeles | CA | USA |
| 7342 | Remi Retail Communications, LLC | Greensburg | PA | USA |
| 7364 | Remi Retail Communications, LLC | Greensburg | PA | USA |
| 7411 | RESTRICTED-Unavailable for assignment until further notice | | | USA |
| 7767 | RNK, Inc. | Dedham | MA | USA |
| 8411 | RESTRICTED-Unavailable for assignment until further notice | | | USA |
| 9411 | RESTRICTED-Unavailable for assignment until further notice | | | USA |