- CIHAN GEMI ELEKTRONIGI Elektrik ve Elektronik San. Ve Tic. Ltd. Sti.
- Citreon-Messian-Durand
- CLA-VAL UK Limited
- Class Instrumentation Ltd
- Classic Automation LLC
- CleanAIR Systems, Inc.
- Cleemann Chair-Systems GmbH
- Clements Engineering (St Neots) Ltd
- Click Bond, Inc.
- CLIMAX GmbH
- Cloud Company Inc
- CLYDEUNION Pumps
- CM Technologies GmbH (formerly Kittiwake GmbH)
- CMI Marine
- CMR Controle Mesure Regulation
- CNAi
- CNIM
- COATES OFFSHORE
- Cofi s.r.l.
- Coldharbour Marine Ltd
- ColorLight AB
- Coltec Ind - Fairbanks Morse
- Coltraco Ltd
- COMBIMAC B.V.
- COMET GMBH
- Compass Marine Services
- Compass Water Solutions
- COMPRESSED AIR CENTRE
- COMSYSTEMS Solutions
- CONRAC GmbH
- Consilium AB
- Consilium Marine & Safety AB
- Consilium Marine Systems BV
- CONSTRUCTION PLANT OF LIFTING EQUIPMENT ZBUD Ltd.
- CONVOTHERM Elektrogeraete GmbH
- Cooper Gitiesse S.r.l.
- Cooper Roller Bearings Co Ltd
- Coops en Nieborg B.V.
- Copes-Vulcan Inc
- Corrosion & Water-Control Shared Services BV
- COSALT BV (Survitec Group)
- Cosalt GmbH
- Cosalt Head Office
- Coupling Corporation America
- Cramer Systemtechnik GmbH
- Cramm Yachting Systems
- Crestchic Loadbanks
- Crewsaver Marine Equipment
- Croon Elektrotechniek BV
- CSD Sealing Systems - North America, LLC
- Cummins Inc.
- Cygnus Instruments Ltd
- D I DAVIT INTERNATIONAL GmbH
- Damen Anchor & Chain Factory (AKF)
- DAPE Consultants, Engineering & Representatives Ltd.
- Dasic Marine Ltd
- DATA HIDROLIK MAKINA SANAYI AS
- Datema Delfzijl BV
- Davey & Company London Ltd
- De Gerlien-Van Tiem BV
- DECKMA GmbH
- Deckma Hamburg GmbH
- DEGUSAN DENIZCILIK SAN. TIC. Ltd. Sti.
- Deif (UK) Ltd
- DELMAR DENIZCILIK TASIMACILIK TURIZM SANAYI VE TICARET Lyd. Sti.
- Delta Fire Ltd
- DELTA GEMI DONATIM LTD. STI
- Delta Rigging and Tools
- DENIZSAN GROUP OF COMPANIES
- Dennis Nakakita SA
- DENO COMPRESSORS
- DENPAR MAKINA A.S.
- DESARROLLO TECNICAS INDUSTRIALES DE GALICIA S.A.
- DESMI B.V.
- DETEGASA
- DEUTZ AG
- Diesel Systems Plant
- DIKO ELEKTRIKLI CIHAZLAR SAN. VE TIC. AS
- DINO PAOLI SRL
- DLK Ventilatoren GmbH
- Dolphin Maritime Software Ltd
- Dometic Marine
- DOORMET Ltd.
- DOUBLE D MARINE EQUIPMENT BV
- Dr. E. Horn GmbH
- Dr. Shrink, Inc.
- Drahtseilwerk GmbH
- DRUMET Ropes and Wires Ltd.
- DSB Offshore Ltd
- Duncan Propellers Ltd
- Duramax Marine LLC
- Durapipe UK(Head office)
- DURASTIC Ltd.
- Dutch Thrustleader Marine Propulsion B.V.
- Dutchi Motors B.V.
- Dutton-Lainson Company
- DYNALCO
- Dynamar B.V.
- Dynamic Marine Systems B.V.
- Eaci Orfeo International