| 1 | SDN | Spirt of Africa Airlines | Callsign: Falair, ICAO Callsign changed to Blue Nile | SUD | AVCODES |
| 2 | SDN | Spirt of Africa Airlines | Callsign: Blue Nile, ICAO Callsign changed from Falair | SUD | AVCODES |
| 3 | SDN | Spirit of Africa Airlines | | | ICAO1 |
| 4 | SDN | Schwaben Dampf Neuoffingen e.V. | Neuoffingen | D | privat-bahn.de |
| 5 | SDN | Schwaben Dampf e.V. | | DE | VKM |
| 6 | SDNA | SCERNI DI NAVIGAZIONE S R L | | | SCAC4 |
| 7 | SDNB | SPECIAL DISTRIBUTION MARYLAND LLC | | | SCAC4 |
| 8 | SDND | SUDDEN IMPACT RACING LLC | | | SCAC4 |
| 9 | SDNG | SUMPTER, DON TRUCKING INC | | | SCAC4 |
| 10 | SDNH | SHANGHAI DINGHENG SHIPPING CO LTD | | | SCAC4 |
| 11 | SDNI | SHERIDAN TRUCKING INC | | | SCAC4 |
| 12 | SDNJ | SAND STONE SERVICES LLC | | | SCAC4 |
| 13 | SDNK | SANDMAN TRUCKING | | | SCAC4 |
| 14 | SDNM | ST DENIS MANUFACTURING | | | SCAC4 |
| 15 | SDNN | S & D TRANSPORT INC | | | SCAC4 |
| 16 | SDNO | STANDARD DISTRIBUTION CO | | | SCAC4 |
| 17 | SDNQ | STEWART, DON A INC | | | SCAC4 |
| 18 | SDNR | SAN DIEGO NORTHERN RAILWAY | | | PWRC |
| 19 | SDNR | San Diego Northern Railway | | | RSRV |
| 20 | SDNR | SIDNEY TRANSPORT LTD | | | SCAC4 |
| 21 | SDNT | STD TRANSPORT LTD | | | SCAC4 |
| 22 | SDNU | SEDNA CONTAINERS B.V. | | NL | BIC |
| 23 | SDNW | SNUG DUE SOCIETA NAVALI UNITE GENOV | | | SCAC4 |
| 24 | SDNX | North County Transit District d/b/a San Diego Northern Ry. | 7/2005 (not listed) | | NAKINA |
| 25 | SDNX | NORTH COUNTY TRANSIT DISTRICT d/b/a SAN DIEGO NORTHERN RAILWAY | | | PWRC |
| 26 | SDNX | SAN DIEGO NORTHERN RAILWAY | | | SCAC4 |
| 27 | SDNX | San Diego Northern Railway | | USA | TRAFFIC |
