Subsea 7 SA provides pipelay, heavy lift, and diving services in addition to engineering and project management services . Operations are divided between two business units: Subsea & Conventional (Subsea 7 and i-Tech 7) and Renewables & Heavy Lifting (Seaway 7). The company is registered in Luxembourg with common shares listed on the OSL (SUBC) exchange.
Stolt-Nielsen Seaway was established in 1973 to provide diving services in the North Sea. The SubSea Offshore division of Brown & Root begins operating in the North Sea the same year. Diving company Wharton Williams (2W) was formed in 1976 and acquired by Brown & Root in 1988. 2W and Smit formed a joint venture called Rockwater in 1990. In separate transactions, Stolt-Nielsen Seaway and Comex Services are acquired by SNSA in 1992. SubSea was acquired by Dresser in 1994.
DNSD acquired Brazil-based Consub in 1997 while Brown & Root acquired 100% holding in Rockwater. In 1998, Halliburton acquired Dresser and combined SubSea and Rockwater to form Halliburton Subsea in 1999. Stolt Comex Seaway acquired Ceanic in 1998 and France-based ETPM in 1999, renaming itself Stolt Offshore in 2000. In 2000, Halliburton and DNSD formed 50-50 joint venture Subsea 7. DNSD acquired Halliburton's share in Subsea 7 in 2005 and lists the company on the Oslo stock exchange. Stolt Offshore changed its name to Acergy in 2006. In 2011, Subsea 7 was formed through the merger of Subsea 7 and Acergy. Subsea 7 acquired Swagelining in 2016 and 4Subsea in 2019.
John Evans replaced Jean Cahuzac as CEO in 2020, and the company announced layoffs of 3,000 people by the end of the second quarter in 2021. The company agreed to combine Seaway 7 with OHT in July 2021, retaining the Seaway 7 name and OHT's public listing. In August 2021, the company agreed to acquired a majority stake in Nautilus Floating Solutions.