Allseas is a privately owned offshore contractor with its group head office at Route de Pra de Plan 18 in Châtel-Saint-Denis, Switzerland. From there it directs the commercial and financial side of a business that installs pipelines and subsea infrastructure, transports and installs platform topsides and jackets, removes redundant platforms in single lifts, and is developing technology to collect polymetallic nodules from the deep seabed. The company was founded in January 1985, when it opened offices in Switzerland and The Hague, and it describes itself as a family business that funds its own projects.
What the company does
Four established activities make up the core of the business. Offshore pipelay covers the installation of rigid steel pipelines in shallow and deep water. Platform transportation and installation uses single-lift methods to place very large topsides and jackets. Platform decommissioning reverses that process, taking complete facilities ashore for dismantling. A fourth, newer line covers polymetallic nodule collection, and the company has also added a nuclear business line. Supporting all of these are in-house design and engineering teams and a fleet built to the company's own specifications.
Vessels and equipment
The best-known unit is Pioneering Spirit, a twin-hull construction vessel built for single-lift installation and removal of complete platform topsides. Solitaire and Audacia are the main pipelay vessels, and Lorelay, the world's first dynamically positioned pipelay vessel, remains in service four decades after it was launched. Sandpiper is a fully automated anchor-positioned pipelay barge used for shallow-water work. Fortitude and Oceanic are offshore construction support vessels used for deepwater installation and for jumper, umbilical and subsea structure work, while Grand Tour is a semi-submersible heavy transport vessel designed to transfer topsides to Pioneering Spirit. Hidden Gem is a deep-sea mineral production vessel with seabed-to-surface nodule collection and transport systems. The fleet is completed by purpose-built cargo barges and dynamically positioned pipe supply vessels that keep line pipe and project materials moving offshore.
Four decades of pipelay firsts
Allseas began by inventing dynamic positioning pipelaying and building Lorelay, launched in 1986, which gave it a foothold in North Sea small and medium diameter pipeline work. The company set out its single-lift concept for large integrated topsides in 1987 and added the trenching support vessel Trenchsetter in 1989. It moved into United States waters in the early 1990s and acquired a bulk carrier in 1992 for conversion into Solitaire, bringing its automatic welding system Phoenix into service in 1993. Lorelay set a deepwater record by laying rigid pipe at 1,645 m on Shell's Mensa project in 1996, and Solitaire installed half of the Europipe II gas export line between Norway and Germany in 1998. Audacia and the trenching vessel Calamity Jane joined the fleet in the mid-2000s, equipped with the company's own ROV systems. In 2010 Allseas committed to building a single-lift platform removal and installation vessel, with the hull constructed by DSME in South Korea, and in 2013 it won the contract to decommission four of Shell's Brent platforms.
Campaigns and milestones in 2026
The company's news list shows continuous project activity during the year. In January 2026 it marked a milestone on the Yongan-Tongxiao 2 project, and in February the new cargo barge Braveheart left for Rotterdam. April brought the fortieth anniversary of Lorelay's entry into service. In July Allseas was selected to install the critical subsea section of the Prince Rupert Gas Transmission pipeline, following an award in November 2025 to install a 500 km pipeline system for Enbridge in the United States Gulf. August marked a decade of single-lift work and the delivery ashore of the North Cormorant topsides. In September the company announced a hybrid-electric ROV fleet and cut first steel for Grand Tour.
Offices and yards
Engineering and project work is handled from Delft, Eindhoven and Enschede in the Netherlands, supported by regional companies in Perth, Spring in Texas and Kuala Lumpur. The company publishes full postal addresses and telephone numbers for each location on its offices page; no general enquiry e-mail address is published anywhere on the site, and the only mailbox that appears is an internal human resources address given in the privacy policy for data protection requests.