- Jahnel-Kestermann Get Bochum
- James Walker Deutschland GmbH
- Jan De Nul n.v.
- Jansen Maritim GmbH & Co. KG
- Japan Radio Co. Ltd.
- JASTRAM GmbH & Co. KG
- Jensen & Rhoden Europe Marine Control AS
- John Gjerde AS
- Johnson Matthey Catalysts (Germany) GmbH
- JOTRON SatCom AS
- JOWA AB
- JS COCK AS
- Kalkman Scheepstechniek BV
- KARBERG & HENNEMANN GmbH & Co. KG
- Karl Dose GmbH
- Karmoy Hire AS
- Karmoy Winch AS
- Kawasaki Precision Machinery UK Ltd
- KELVIN HUGHES
- Kelvin Hughes Nederland BV
- KET Marine BV
- Kettenfabrik Mester GmbH
- Keytouch Technology
- KGW SCHWERINER MASCHINENBAU GMBH
- KIESS GmbH & Co. KG
- Kistler Bw Prazisionstechnik GmbH
- KLH Montage GmbH
- KM Europa Metal AG
- KNAACK & JAHN GmbH-Pipeline and plant construction
- Knaack & Jahn Schiffbau GmbH
- Knowsley Instrument Serv Ltd
- KOCKUM SONICS AB
- Koerting Hannover AG
- Kohler Co., Kohler Power Systems
- Kolmer Elektromotoren BV
- KOMPRESSORENBAU BANNEWITZ GmbH
- Konecranes Lifttrucks AB
- Kongsberg Maritime
- Kongsberg Maritime AS (formerly SIMRAD SUBSEA A/S)
- Koning Technisch Bedrijf BV
- KPM Marine D E Ltd
- KRACHT GmbH
- KRANUNION GmbH - Kirow, Ardelt & Kocks are members of KRANUNION
- Kreisler Import BV
- KROHNE Messtechnik GmbH & Co. KG
- KROHNE Skarpenord
- KULA Lautenschlager GmbH & Co. KG
- Kumera
- Kupke & Wolf GmbH
- KWANT CONTROLS B.V.
- Kyma AS
- LAB GMBH
- LAGERSMIT
- Lawson Engineers Ltd
- LEC Marine Ltd
- LEHMANN & MICHELS GmbH
- Leistritz Pumpen GmbH
- LEMANS NEDERLAND BV
- LIEBHERR MARITIME BENELUX BV
- Lift Emotion BV
- Lift-Tex Industrie BV
- Liftcom BV
- Lifting & Marine Services Ltd
- Liftra ApS
- Linde Hydraulics
- Lindenberg-Anlagen GmbH
- LINKSrechts Ingeniergesellschaft mbH
- Littelfuse SELCO A/S
- Loggers Schwingungstechnik GmbH
- Loher GmbH
- LONNE SCANDINAVIA AS
- Lopolight ApS
- LOTEK A/S
- LSM Pumper
- LYNGSO MARINE A/S
- M.Juergensen GmbH & Co KG
- MacArtney A/S
- MacGregor HYDRAMARINE AS
- MacGregor Marine Equipment Ltd
- Machine- & Lierenfabriek C. Kraaijeveld BV
- Machinefabriek L. Straatman BV (Formerly Van de Graaf's werktuig en constructiebouw)
- Machinefabriek Luyt BV
- MACOR Marine GmbH
- Magotteaus
- MAHLE INDUSTRIEFILTRATION GMBH
- MAN B&W DIESEL A/S
- MAN Engines & Components UK
- Manfred J.C. Niemann - Marine Division
- Mantsbrite Marine Electr
- Marco Marine A/S
- MARE SAFETY AS
- Mareflex GmbH
- MARES SHIPPING GmbH
- Marflex B.V.
- MARINE ALUMINIUM AS
- MARINE COMMUNICATIONS Ltd.
- MARINE CONTROL SERVICES AS
- Marine Logistics Limited
- Marine Motor Service GmbH
- Marine Rescue Technologies Ltd