N-Sea

What N-Sea does

N-Sea is an integrated subsea infrastructure services provider headquartered in Dordrecht, Netherlands, with origins in Zierikzee and operations across Europe (Netherlands, United Kingdom, Poland) and the Middle East (United Arab Emirates, Saudi Arabia). The company delivers end-to-end subsea solutions across five core service lines — Survey, UXO ID & Disposal, IRM & Construction, Subsea Cable Repair & Installation, and Data Management — serving offshore energy developers and operators in the renewable energy, oil & gas, and utilities sectors. Revenue exceeded €200M in 2025, generated primarily through project-based contracts and framework agreements with enterprise clients, using a fleet of 14 multipurpose vessels and approximately 500 onshore and offshore professionals.

The company's technical platform centres on the in-house developed MagSense vertical gradiometer array for high-accuracy UXO detection in magnetically noisy subsea environments, supported by an in-house data centre capable of remote processing and reporting across all business lines. N-Sea operates the dedicated cable repair vessel CURO (8-point mooring, beaching capability) for nearshore and high-tidal work, and is currently commissioning two newbuild vessels — the methanol-ready DP2 vessel Altera and the newbuild Dominus — to extend fleet capacity through 2026-2027. Certifications include ISO 9001 (Quality), ISO 14001 (Environmental), ISO 45001 (Occupational Health & Safety), and Safety Culture Ladder Level 3.

N-Sea monetises services through direct enterprise sales, multi-year framework agreements (most notably a 7-year arrangement with Prysmian for submarine cable repair and maintenance using dedicated assets and a mobile cable repair spread), and project-specific tenders. Named enterprise customers include Prysmian and OFTO transmission asset owners such as Gwynt y Môr. The company is privately held following an April 2021 change of ownership and fully repaid its long-term subordinated debt to Aegon Achtergestelde Leningen Fonds in April 2025.

Name

N-Sea

Legal name

N-Sea Group BV

Website

https://n-sea.com

Company type

Private

Founded year

2006

Operating status

Operating

Headcount range

101–250 employees

Short description

N-Sea is a Netherlands-headquartered integrated subsea infrastructure services provider delivering survey, UXO clearance, cable repair, IRM and construction, and data management to offshore wind, oil & gas, and utility clients across Europe and the Middle East using a fleet of 14 multipurpose vessels.

Ownership category

akta.pro rank

Product category

Subsea Services

NAICS

Other Support Activities for Water Transportation (48839), Support Activities for Water Transportation (4883)

SIC

Oil & Gas Field Services, Nec (1389)

akta.pro primary industry

Marine & Offshore Energy O&M (Offshore Wind, Platforms, Subsea Assets) (EUAEAGAO)

akta.pro secondary industries

Offshore Marine & Aviation Support (PSVs, AHTS, Crew Boats, Helicopters) (EUALABAJ), Underwater Inspection, Maintenance & Repair (UWILD, Diving/ROV, In-water Cleaning) (IMAJAFAJ)

Keywords

• Subsea cable services
• Offshore survey services
• UXO detection disposal
• Subsea inspection maintenance
• Offshore wind infrastructure

Headquarters

HQ city

Zierikzee

HQ country

Netherlands

HQ region

Europe

Offices9 records

Markets served

GTM type

B2B

Offering type

Services

Cost components

Personnel, Operations, Infrastructure, Technology or R&D, Marketing or Sales

Revenue model

1. Subsea Services: N-Sea generates revenue through providing integrated subsea services including survey, UXO ID & disposal, IRM & construction, subsea cable repair & installation, and data management. Revenue is project-based, typically through contracts and framework agreements with offshore energy clients. Revenue exceeded €200M in 2025.

Go-to-market motion1 record

Distribution channels1 record

Marketing channels5 records

Core offering

N-Sea is an integrated total subsea solutions provider delivering five core service lines — Survey, UXO ID & Disposal, IRM & Construction, Subsea Cable Repair & Installation, and Data Management — across the full offshore project lifecycle. Services are executed using a fleet of 14 multipurpose vessels and dedicated in-house divisions, and are sold to international offshore energy, renewable energy, oil & gas and utility clients on a project or framework-agreement basis.

Product overview

N-Sea is an integrated total subsea solutions provider offering five core service lines: Survey, UXO ID & Disposal, IRM & Construction, Subsea Cable Repair & Installation, and Data Management. The company delivers end-to-end subsea services for the offshore energy lifecycle using a fleet of 14 multipurpose vessels and in-house systems. Services are offered both as standalone capabilities and as integrated solutions combining multiple service lines. N-Sea serves the international oil & gas, renewable energy, and civil contracting industries.

Differentiator

Problem solved

Functional benefit

Brands

• MagSense: A vertical gradiometer array specifically designed for highly accurate UXO (Unexploded Ordnance) campaigns, developed in-house by N-Sea.

Products and services

• Survey Offshore survey services for data acquisition essential for subsea energy developers and asset owners. Capabilities include analogue geophysical survey, 2D/3D ultrahigh resolution surveys, pipeline and cable inspections, environmental surveys, geotechnical surveys, ROV & ROTV survey, and data management, supporting offshore wind, oil & gas and transmission infrastructure clients.
• UXO ID & Disposal Unexploded ordnance detection, identification, clearance and removal services for offshore energy infrastructure projects. Features the in-house developed MagSense vertical gradiometer array for highly accurate UXO campaigns in magnetically noisy subsea environments.
• IRM & Construction Inspection, Repair, Maintenance, Construction and Decommissioning services for subsea infrastructure. Covers the entire project lifecycle from design through operations to decommissioning for offshore energy and transmission assets.
• Subsea Cable Repair & Installation Complete and fully integrated subsea cable solutions covering each phase of the client's asset life cycle — design, construction, operations and decommissioning. Includes shallow water installation, HDD duct support, CPS stabilisation and multi-year framework agreements for export and interconnector cables.
• Data Management In-house data centre services providing expertise in forefront technologies, supporting all aspects of the company's business lines across the project lifecycle including planning, real-time technical support, in-house data processing, reporting and remote data management capabilities.

Named customers2 records

Segments3 records

Ideal customer profiles3 records

Technology focussed No

API detail

Has API

No

API docs

API detail

Core technology

AI maturity

App detail

Feature1 record

Partnerships

Six partnerships are on record, tiered core and major.

• GeoForce Technical ServicescoreStrategic or Co-development Partner · 11 March 2026Partnership announced March 2026 to offer fully integrated shallow water geotechnical solution. Beginning Q2 2026, GeoForce deploys bespoke geotechnical package permanently integrated onto N-Sea vessel. Services include seabed characterisation, sediment analysis, core penetration testing, and integrated deliverables supporting ground model development.
• Rederij GroenmajorTechnology or Integration · 9 March 2026Long-term charter agreement for newbuild offshore support vessel Dominus. Vessel being constructed by PASSER at Shipyard De Hoop in Tolkamer, Netherlands. Keel laying ceremony took place late February 2026. Delivery scheduled for April 2027. Vessel features diesel-electric propulsion with Tier 3 engines for reduced emissions.
• Shipyard De HoopmajorTechnology or Integration · 9 March 2026Vessel construction partner building Dominus at Shipyard De Hoop in Tolkamer, Netherlands, in collaboration with PASSER.
• PASSERmajorTechnology or Integration · 9 March 2026Vessel builder constructing Dominus offshore support vessel in partnership with Shipyard De Hoop. Lars-Fredrik Bakke serves as CEO of PASSER.
• Neptune MarinemajorTechnology or Integration · 11 April 2025Trusted partner building new multi-purpose shallow draft vessel 'Altera' for N-Sea. Vessel under construction in Poland, scheduled to transfer to Netherlands Q4 2025 for fitting and commissioning Q2 2026. DP2 vessel dual fuel methanol prepared with 25t offshore knuckle boom crane.
• PrysmiancoreStrategic or Co-development Partner · 3 April 20257-year framework agreement announced April 2025. N-Sea delivers full suite of repair and maintenance services for export and interconnector cables including dedicated vessel CURO and mobile subsea cable repair spread mobilised from Operations Support Base in IJmuiden. This partnership provides Prysmian with rapid response provision and a unique one-stop-shop solution for the global high voltage submarine cable market.

Scale indicators4 records

Recent moves6 records

Expansion highlights6 records

Direct peers

• DeepOcean: Independent subsea services provider offering survey, IRM, and cable installation across offshore wind and oil & gas. Closely comparable in service mix, vessel-based delivery model, and North Sea focus to N-Sea.
• Fugro: Global leader in offshore site investigation, geophysical and geotechnical survey, and subsea services. Direct overlap with N-Sea's Survey and IRM lines, including the recent partnership with GeoForce (part of the Venterra/Oceanscan group) bringing geotechnical capability to N-Sea's vessels.
• Helix Energy Solutions Group: Provider of subsea well intervention, IRM, and cable/flowline services to the offshore industry. Comparable in integrated subsea IRM and trenching capability, though more focused on deepwater oil & gas.
• MMT Group: Swedish-headquartered subsea survey and seabed mapping specialist serving offshore wind and oil & gas. Closely comparable to N-Sea's survey and UXO detection service lines, particularly in European offshore wind.

Broad incumbents

• Van Oord: Dutch marine contractor with major offshore wind and cable installation business. Direct overlap with N-Sea in subsea cable lay, UXO clearance, and survey for European offshore wind projects.
• Subsea 7: Global integrated subsea contractor offering SURF, IMR, and renewables services with a much larger fleet. Comparable to N-Sea across subsea cable installation, IRM, and survey, but operates at a significantly larger scale and with deepwater focus.
• Saipem: Global engineering and offshore services major with subsea cable lay, SURF, and IRM capabilities. Overlaps with N-Sea in subsea cable installation and survey, though Saipem operates across the full offshore value chain at much larger scale.
• Boskalis: Large Dutch offshore services and dredging contractor with a dedicated subsea services arm (Boskalis Subsea Services). Overlaps directly with N-Sea on subsea cable installation, survey, and IRM for offshore wind and oil & gas in the North Sea.
• Jan De Nul Group: Belgian marine contractor active in offshore cable installation, subsea rock installation, and offshore wind balance of plant. Competes with N-Sea in subsea cable and survey work for European offshore wind.

Regional players

• Volker Stevin (VolkerWessels): UK-based marine and civil contractor with offshore and nearshore subsea capabilities, competing with N-Sea in North Sea cable and IRM work for offshore wind transmission assets.

Market position

Strengths5 records

Weaknesses5 records

Competitive moat5 records

Key risks6 records

Key highlights7 records

Customer concentration

• Facebookfacebook.com/nseagroup
• LinkedInnl.linkedin.com/company/n-sea-group
• Instagraminstagram.com/nsea_official

Compliance4 records

Revenue estimate

Valuation estimate

Number of profiles

Profiles9 records

Subsidiaries3 records

Funding overview

Funding rounds2 records

Investors2 records

Funding detail is available on the Subscription and Enterprise plan.Contact sales →

M&A

Investments

M&A and investment is available on the Subscription and Enterprise plan.Contact sales →

Frequently asked questions about N-Sea