What OOS International does

OOS International (legal name Overdulve Offshore Services) is a Netherlands-based offshore service provider founded in 2009 and headquartered at Villa Welgelegen in Serooskerke. The company serves the oil and gas industry with a fleet of specialized marine assets spanning semi-submersible crane vessels (SSCV OOS Gretha, Serooskerke, Walcheren, Zeelandia), a semi-submersible accommodation unit (SSCU OOS Prometheus), an accommodation/multi-service vessel (SSUMS OOS Tiradentes), a multi-function vessel (SSMF OOS Cees Leenaars), and a rigid crane/support vessel (RCS OOS MS Switzerland). It is led by founder and CEO Léon Overdulve and operates as part of the broader OOS Group alongside sister brands OOS Energy, OOS Logistics, OOS Catering, and OOS Safety.

The company's commercial offering is organized around four service lines: heavy lift installation, offshore accommodation, decommissioning, and ship management (including engineering, maintenance, and operational services). It sells primarily through direct enterprise B2B sales to oil and gas clients globally, with offices in multiple countries serving as commercial focal points. Revenue mechanics are project-based B2B service contracts negotiated by scope, vessel requirement, and duration, with no publicly disclosed pricing. A strategic joint venture with Bluewhale Offshore, branded BlueOOS, combines accommodation and vessel management capabilities, and the company has also added a Mussel Farm service line leveraging existing marine infrastructure for aquaculture diversification. The company is privately held, founder-owned, and shows no evidence of external institutional or PE/VC capital in the available materials.

Name

OOS International

Legal name

Overdulve Offshore Services (OOS International)

Website

https://oosinternational.com

Company type

Private

Founded year

2009

Operating status

Operating

Headcount range

101–250 employees

Short description

OOS International is a Netherlands-based offshore service provider operating a fleet of specialized semi-submersible vessels for heavy lift, accommodation, decommissioning, and ship management, primarily serving the global oil and gas industry.

Ownership category

akta.pro rank

Product category

Offshore Support Services

NAICS

Support Activities for Water Transportation (4883), Ship Building and Repairing (336611)

SIC

Oil & Gas Field Services, Nec (1389), Ship & Boat Building & Repairing (3730)

akta.pro primary industry

Offshore Marine & Aviation Support (PSVs, AHTS, Crew Boats, Helicopters) (EUALABAJ)

akta.pro secondary industries

Marine & Offshore Energy O&M (Offshore Wind, Platforms, Subsea Assets) (EUAEAGAO), Pipe-lay & Heavy-lift Offshore Vessel Construction (IMAJACAE), Offshore Vessel Life Extension, Major Conversion & Rebuild (EPC/Integration) (IMAJACAJ)

Keywords

• Offshore vessel services
• Heavy lift installation
• Marine accommodation services
• Ship management services
• Offshore decommissioning

Headquarters

HQ city

Serooskerke

HQ country

Netherlands

HQ region

Europe

Offices1 record

Markets served

GTM type

B2B

Offering type

Services

Cost components

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

Distribution channels1 record

Marketing channels4 records

Core offering

OOS International owns and operates a fleet of advanced marine assets — semi-submersible crane vessels (SSCV), semi-submersible accommodation vessels (SSCU), and semi-submersible accommodation/support units (SSUMS) — to deliver heavy lift installation, offshore accommodation, ship management, and decommissioning services to the global offshore oil and gas industry. The company offers both single-service engagements and integrated one-stop-shop offshore solutions from its head office in Serooskerke, The Netherlands.

Product overview

OOS International is an offshore service provider offering a fleet of specialized marine vessels and services for the oil and gas industry. The company operates a fleet of semi-submersible crane vessels (SSCV), semi-submersible accommodation vessels (SSCU), and accommodation vessels providing heavy lifting, decommissioning, ship management, and accommodation services. The portfolio includes SSCV OOS Gretha, SSCU OOS Prometheus, SSCV OOS Serooskerke, SSCV OOS Walcheren, and SSCV OOS Zeelandia, among others. The company also offers mussel farming services and has launched BlueOOS as a joint venture with Bluewhale Offshore. Services range from single offerings to one-stop-shop integrated solutions for offshore projects.

Differentiator

Problem solved

Functional benefit

Products and services

• Heavy Lifting
• Decommissioning Offshore decommissioning solutions for end-of-life offshore infrastructure and equipment removal, provided to operators needing safe dismantling and recovery of offshore assets.
• Ship Management Professional vessel management services for offshore ships and maritime assets, including engineering, maintenance, and operational support delivered to offshore clients.
• Accommodation Offshore accommodation services providing lodging and support facilities for offshore personnel, utilizing the company's fleet of semi-submersible accommodation vessels.
• Mussel Farm Mussel farming services utilizing the company's offshore marine infrastructure, representing a diversification of offshore asset use beyond oil and gas.

Segments1 record

Ideal customer profiles1 record

Technology focussed No

API detail

Has API

No

API docs

API detail

Core technology

AI maturity

App detail

Feature4 records

Partnerships

One partnership is on record.

• Bluewhale OffshorecoreStrategic or Co-development PartnerBluewhale Offshore and OOS Group partnership marked a next phase with signed agreement and launch of BlueOOS, a combined entity for enhanced offshore service delivery. The BlueOOS brand represents the joint venture between Bluewhale Offshore and OOS Group.

Scale indicators2 records

Recent moves4 records

Expansion highlights5 records

Direct peers

• DOF Group: DOF Group operates a global fleet of offshore support vessels (OSVs), including AHTSs, PSVs, and accommodation vessels. It competes directly with OOS in offshore vessel management and accommodation services for oil & gas operators, though with a broader and more conventional OSV fleet.
• Heerema Marine Contractors: Heerema is a leading offshore heavy-lift and transportation/installation contractor operating one of the world's largest SSCV fleets. It directly competes with OOS in heavy lift installation and decommissioning of offshore structures and shares the same client base of international oil & gas majors.
• Solstad Offshore: Solstad Offshore is a Norwegian offshore support vessel owner and operator with a large fleet of AHTSs, PSVs, and specialized offshore vessels. It shares OOS's offshore vessel management business model and competes for similar offshore accommodation and support contracts in the North Sea and beyond.
• Vallianz Holdings: Vallianz is a Singapore-based offshore support vessel operator providing accommodation, heavy lift, and offshore services to oil & gas clients. It is directly comparable to OOS as a smaller, specialized OSV and accommodation provider competing for similar offshore contracts in emerging and mature markets.

Broad incumbents

• Van Oord: Van Oord is a Dutch family-owned marine contractor specializing in dredging, offshore wind, and offshore oil & gas installation. It competes with OOS in offshore installation, accommodation support, and increasingly in offshore wind, with broader capabilities and a larger fleet.
• Subsea 7: Subsea 7 is a major subsea engineering, construction, and services company with offshore vessel capabilities including heavy-lift and accommodation. It overlaps with OOS in subsea installation, SURF projects, and offshore personnel accommodation services for the same IOC client base.
• McDermott International: McDermott is a global offshore EPC contractor providing integrated solutions for offshore oil & gas, including heavy lift installation and decommissioning. It directly overlaps with OOS in heavy lift EPCI and competes for the same major project tenders.
• TechnipFMC: TechnipFMC is a large subsea and offshore project contractor serving the oil & gas industry with integrated engineering, manufacturing, and installation services. It competes with OOS in offshore installation and project execution for the same international client base.
• Saipem: Saipem is a global offshore engineering, procurement, construction, and installation contractor serving oil & gas and renewables. It competes with OOS in heavy lift installation and offshore decommissioning, offering integrated EPC capabilities that exceed OOS's bundled service scope.
• Boskalis: Boskalis is a large Dutch-headquartered maritime services company active in offshore energy, heavy lifting, and subsea services. It overlaps with OOS across offshore installation, accommodation, and decommissioning, but operates at materially larger scale with a much broader service portfolio.

Market position

Strengths4 records

Weaknesses4 records

Competitive moat4 records

Key risks5 records

Key highlights6 records

Customer concentration

• Facebookfacebook.com/BlueOOS
• LinkedInlinkedin.com/company/oos-international
• Instagraminstagram.com/blue_oos
• Xx.com/oos_intl

Revenue estimate

Valuation estimate

Number of profiles

Profiles1 record

Subsidiaries1 record

Funding overview

Funding rounds

Investors

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 OOS International