| 1 | OCS | Ocean Sky Aviation Ltd | Callsign: Ocean Sky, Ceased operations. | GB | AVCODES |
| 2 | OCS | CoyotAir, S.A. | Callsign: Yoco, | E | AVCODES |
| 3 | OCS | Ocean Sky (UK) | | | ICAO1 |
| 4 | OCSA | OCEANICA, S. A. | | | SCAC3 |
| 5 | OCSA | ORIENT CHAMPION SHIPPING COMPANY LI | | | SCAC4 |
| 6 | OCSC | OCEANIC CREST SHIPPING COMPANY LIMI | | | SCAC3 |
| 7 | OCSD | OCEANSIDE SHIPPING ENE | | | SCAC4 |
| 8 | OCSF | OCEANSIDE FISHERIES INC | | | SCAC4 |
| 9 | OCSG | OCS LOGISTICS | | | SCAC4 |
| 10 | OCSH | OCEANIC SHIPPING COMPANY OF GEORGIA | | | SCAC3 |
| 11 | OCSH | OCEAN COMMAND SHIPPING COMPANY LIMI | | | SCAC4 |
| 12 | OCSI | OCS TRANSPORTS INC | | | SCAC3 |
| 13 | OCSI | OCEAN AGENCIES INC | | | SCAC4 |
| 14 | OCSJ | ORIENT CENTAUR SHIPPING COMPANY LIM | | | SCAC4 |
| 15 | OCSK | OCEAN CRYSTAL SHIP AND SEATRADE INC | | | SCAC4 |
| 16 | OCSL | OCEANFOCUS SHIPPING LTD OWNERS OF M | | | SCAC3 |
| 17 | OCSL | OCEANFOCUS SHIPPING LTD OWNERS OF M | | | SCAC4 |
| 18 | OCSM | AMERICAN PRESIDENT INTERMODAL COMPANY | | | PWRC |
| 19 | OCSN | OCEAN CREST SHIPPING COMPANY LIMITE | | | SCAC4 |
| 20 | OCSO | OCEAN COMPASS SHIPPING COMPANY LIMI | | | SCAC4 |
| 21 | OCSP | OCS TRANSPORT SERVICES INC | | | SCAC4 |
| 22 | OCSR | OCEAN CURRENT SHIPPING COMPANY LIMI | | | SCAC4 |
| 23 | OCSS | OCEANIC STEAMSHIP LINES | | | PWRC |
| 24 | OCSS | OCEANIC STEAMSHIP COMPANY, THE | | | SCAC3 |
| 25 | OCSS | OCEANIC STEAMSHIP COMPANY, THE | | | SCAC4 |
| 26 | OCSU | SCRIPPS INSTITUTE OF OCEANOGRAPHY | | | PWRC |
| 27 | OCSU | Scripps Institute of Oceanography | | | RSRV |
| 28 | OCSU | OVERSEAS CONTAINER LTD | | | SCAC3 |
| 29 | OCSU | OVERSEAS CONTAINER LTD | | | SCAC4 |
| 30 | OCSV | OCEAN CHARIOT SHIPPING COMPANY LIMI | | | SCAC4 |
| 31 | OCSX | Omaha Cold Storage Co. (North Western Refrigerator Line Co.) | 7/1935 | | NAKINA |
| 32 | OCSX | Omaha Cold Storage Co. | 7/1932 | | NAKINA |
| 33 | OCSX | OMAHA COLD STORAGE CO. | | | PWRC |
| 34 | OCSY | ORIENT CAVALIER SHIPPING COMPANY LI | | | SCAC4 |
