Work on the transformational project at the Outer Hebrides’ main port is expected to start in the coming weeks and be completed before the end of next year.
Initial work to develop the new facility will include piling activity, blasting of 750,000 tonnes of rock and dredging.
McLaughlin and Harvey is based in Belfast and has offices in Scotland and throughout the UK.
John Mariner, the company’s Contracts Director (Civil Engineering), said: “We bring the experience from our ever-expanding expertise in marine works and look forward to commencing works in the near future.”
The deep water terminal will be able to accommodate on and offshore wind farm vessels and support other energy sector activity, its main berth will be suitable for the largest cruise liners, to help boost the islands’ important tourism industry.
Development of the terminal will also increase the capabilities and flexibility of the Arnish fabrication yard at Stornoway.
Deputy First Minister John Swinney said: “The development of the Stornoway deep water terminal will be a game changer for the local economy and for Scotland’s aspirations to grow our renewables and cruise sectors.
“The Scottish Government has long been supportive of this project, which will create jobs and multiple economic benefits for the Hebrides.”