| 1 | SIN | Sinair | Callsign: Sinairline, | F | AVCODES |
| 2 | SIN | Servizi Aerei Industriali S.p.A. | Callsign: Infrarosso, | I | AVCODES |
| 3 | SIN | Santair | Callsign: Santair, | GR | AVCODES |
| 4 | SINA | SINCLAIR MOVING & STORAGE INC | | | SCAC4 |
| 5 | SINB | SINOTRANS (BERMUDA) LTD | | | SCAC4 |
| 6 | SIND | Southern Indiana Ry., Inc. | 1/1975-1/1980; eliminated 7/1989; 1/1994-7/2005 | | NAKINA |
| 7 | SIND | Southern Indiana Ry., Inc. | 1/75-1/80; eliminated 7/89; 1/94-7/2000 | | NRHS |
| 8 | SIND | SOUTHERN INDIANA RAILWAY, INC. | | | PWRC |
| 9 | SIND | Southern Indiana Railway | | | RSRV |
| 10 | SINF | SIMARD, N & FRERES INC | | | SCAC4 |
| 11 | SINH | SOUTHERN INDUSTRIAL & TRUCK LTD | | | SCAC4 |
| 12 | SINK | SCISENSE INC | | | SCAC4 |
| 13 | SINL | STRITE INDUSTRIES LIMITED | | | SCAC4 |
| 14 | SINM | SUPERION INC | | | SCAC4 |
| 15 | SINN | SINGER TRANSPORT INC | | | SCAC4 |
| 16 | SINO | SINO-AMERICAN CORP | | | SCAC1 |
| 17 | SINO | SINO CONNECTIONS LOGISTICS LTD | | | SCAC4 |
| 18 | SINP | STIM INTERNATIONAL INC | | | SCAC4 |
| 19 | SINQ | SCAFFS INCORPORATED | | | SCAC4 |
| 20 | SINS | SINDEN RACING SERVICE INC | | | SCAC4 |
| 21 | SINT | SUNTRUCK INC | | | SCAC4 |
| 22 | SINTR | SERVICIOS INDUSTRIALES Y TRANSPORTES, S.A. | | ES | VKM |
| 23 | SINU | BBC CHARTERING GMBH & CO. KG | | D | BIC |
| 24 | SINV | SINCERE NAVIGATION CORPORATION | | | SCAC4 |
| 25 | SINW | SHIP NOW INC | | | SCAC4 |
| 26 | SINZ | SAUDER INDUSTRIES | | | PWRC |
| 27 | SINZR | ŠINVOZ A.D., Zrenjanin | | RS | VKM |
