Subsea7 has published its Annual Report 2025, outlining the financial performance and project activity of its Renewables business unit, which operates under the Seaway7 brand and focuses on fixed offshore wind installation, alongside early-stage floating wind activities.
The Renewables business unit reported revenue of $1.2 billion in 2025, in line with the previous year. Adjusted EBITDA increased to $202 million from $185 million in 2024, resulting in a margin of 16.6%, compared with 15.0% a year earlier. Net operating income reached $75 million, up by $22 million, or 41% year on year. The company attributes this to project execution and a more selective approach to bidding and backlog composition applied since 2022.
The Renewables backlog stood at $2.1 billion at the end of 2025, with $1.1 billion expected to be executed in 2026. Capital expenditure totalled $69 million, slightly lower than $73 million in 2024, and focused on vessel maintenance, repair and minor upgrades. By year end, Seaway7 had supported the installation of nearly 20 GW of offshore wind capacity globally.
United Kingdom
At Dogger Bank (A, B and C), Seaway7 installed 277 monopiles and 277 transition pieces across all three phases by the end of 2025. Vessels Seaway Strashnov and Seaway Alfa Lift carried out foundation and transition piece installation at Dogger Bank C during the year, with turbine installation expected to continue into 2026.
At East Anglia THREE, foundation installation began in March 2025. Vessel Seaway Ventus installed 39 monopiles and 39 transition pieces out of a total scope of 95. The remaining monopiles are planned for installation in 2026, alongside the start of inter-array cable work by Seaway Aimery and Seaway Phoenix.
Preparation work for East Anglia TWO was ongoing in 2025, with cable installation scheduled for 2027. Cable-lay activity also continued at Hornsea 3, while foundation installation at Inch Cape is planned for 2026.
Seaway7 has been active in the United Kingdom offshore wind sector since 2009, with earlier projects including Greater Gabbard, Beatrice, Triton Knoll, Moray West and Seagreen.
Germany
At He Dreiht, described as the largest offshore wind farm in Germany with a capacity of 960 MW, cable laying, trenching and as-trenched survey work covering 95 km was completed in 2025 by Seaway Aimery and Seaway Moxie. The project was nearing completion.
Taiwan
Cable-lay operations continued at Hai Long in 2025 using Seaway Phoenix. The Yunlin and Zhong Neng projects were also approaching completion. A new inter-array cable contract for Formosa 4 and 6 was awarded during the year and added to the backlog.
USA
At the Revolution project, cable-lay work was completed in 2025 by Seaway Aimery.
Poland
Work progressed on the Baltyk II and III cable projects. The BC Wind project was added to the backlog following a new award in 2025.
Order intake
The Renewables business unit reported total order intake of $9.0 billion in 2025, compared with $8.2 billion in 2024 and $7.4 billion in 2023. New awards included the Formosa 4 and 6 inter-array cable contract in Taiwan and the BC Wind project in Poland.
Floating offshore wind
Floating offshore wind activities remained at an early stage and did not contribute significantly to financial results in 2025. Work during the year focused on studies aimed at developing technologies and solutions to support lower-cost floating wind projects. The company notes that project economics continue to affect the pace of development.
Market outlook
The company highlights the United Kingdom’s Allocation Round 7 Contracts-for-Difference auction, announced in January 2026, as relevant for the sector’s longer-term outlook. The auction confirmed that fixed offshore wind projects totalling 8.2 GW are expected to proceed, with installation activity anticipated in 2029 and 2030.
Subsea7 also notes slower progress in other markets, including the Netherlands and Germany. It projects global cumulative fixed offshore wind installations to increase from 44 GW in 2026 to 65 GW in 2029 and 100 GW in 2032.
