SEA-Marine

What SEA-Marine does

SEA-Marine (legal name: SEA Sjöentreprenad och Anläggning AB, Swedish organization number 556941-1126) is a privately held marine infrastructure contractor headquartered in Olofström, Sweden. The company self-describes as a nationwide (rikstäckande) operator within marine infrastructure, delivering specialized services in and around water for government agencies, municipalities, utilities, and industrial clients. Its service portfolio comprises eight lines: underwater concrete work, piers and small boat harbors, bubble curtain systems, underwater inspection, certified PE (polyethylene) welding, silt curtains, submarine cable installation, and marine pipeline installation.

The company's technical differentiators are concentrated in proprietary methods for high-complexity underwater scenarios rather than patented IP. Notable capabilities include a developed method for handling subsea pipelines loaded above 100% of standard pressure ratings (executed at 120% on a 3 km Ø250 pipeline between Tumbo and Österby for Mälarenergi), custom-engineered bubble curtain systems for noise attenuation and ice prevention, dam renovation under continuous lake regulation with locally dewatered formwork (Ronneby Miljö och Teknik, Hängbrunnen), and certified welding under EN 13067, EWF 581-01, and Norwegian Nemko. The workforce holds competency class 1 for on-site concrete placement with additional underwater casting endorsements and Trafikverket batman training. The company is ISO 9001/14001/45001 certified.

SEA-Marine operates as a project-based B2B professional services provider. Revenue is generated through competitive tenders and direct engagements on multi-year contracts, often as prime contractor in totalentreprenad arrangements or as a specialized subcontractor. Pricing is quote-driven and not publicly disclosed; the company offers free cost proposals. Visible customers include Trafikverket, Swedavia (Arlanda Airport), Mälarenergi, Ronneby Miljö och Teknik, and Västanfors kraftstation, spanning government, airport, municipal utility, and power generation end markets. No funding rounds, M&A, leadership changes, or international expansion are evident in the source data.

Name

SEA-Marine

Legal name

SEA Sjöentreprenad och Anläggning AB

Website

https://sea-marine.se

Company type

Private

Operating status

Operating

Headcount range

1–10 employees

Short description

SEA-Marine is a Swedish privately held marine infrastructure contractor providing specialized underwater construction, inspection, certified PE welding, and subsea pipeline and cable installation services to government agencies, municipalities, utilities, and industrial clients across Sweden.

Ownership category

akta.pro rank

Product category

Marine Infrastructure Services

NAICS

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

SIC

Ship & Boat Building & Repairing (3730)

akta.pro industry

PRIMARYIMAFAJAF

Marine Terminals & Cargo Handling Infrastructure (RoRo, Bulk, Container)

Industrials, Manufacturing & Construction/Construction & Civil Engineering/Marine & Coastal Construction (Ports, Harbors, Dredging)

SECONDARYIMAJAFAJ

Underwater Inspection, Maintenance & Repair (UWILD, Diving/ROV, In-water Cleaning)

Industrials, Manufacturing & Construction/Marine & Shipbuilding/Ship Repair, Maintenance & Conversion (MRO)

Keywords

• Marine infrastructure services
• Underwater construction services
• Subsea pipeline installation
• Marine welding services
• Underwater inspection services

Headquarters

HQ city

Olofström

HQ country

Sweden

HQ region

Europe

Offices2 records

Markets served

GTM type

B2B

Offering type

Services

Cost components

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

Revenue model

1. Marine Infrastructure Project Services: SEA-Marine generates revenue through providing specialized marine infrastructure services on a project basis. Services include concrete work, pier/dock construction, underwater inspection, PE welding, bubble curtain installation, silt curtain installation, subsea cable installation, and subsea pipeline installation. Projects are typically awarded through competitive tendering or direct engagement for specialized underwater work. Revenue is project-based, not recurring, with each engagement having distinct scope, duration, and pricing.

Pricing tiers

Go-to-market motion1 record

Distribution channels1 record

Marketing channels3 records

Core offering

SEA-Marine provides specialized marine infrastructure contracting services in and around water, including underwater concrete work, pier and small boat harbor construction, subsea pipeline and submarine cable installation, certified PE/thermoplastic welding, and environmental protection systems (bubble curtains and silt curtains). The company also delivers underwater inspection services for pipelines, cables, concrete/steel structures, and vessel hulls. Services are delivered on a project basis to government agencies, municipalities, utilities, and industrial clients across Sweden.

Product overview

SEA-Marine (SEA Sjöentreprenad och Anläggning AB) is a nationwide marine infrastructure contractor offering a comprehensive portfolio of specialized underwater and marine construction services. The company operates as a service-based business rather than a software product platform. Its core offerings include: concrete work for underwater structures, piers and small boat harbor construction and maintenance, bubble curtain systems for noise reduction and ice prevention, underwater inspection services, PE (polyethylene) welding, silt curtain installation for sediment control, marine cable installation (fiber and power), and marine pipeline installation. The services are delivered as distinct professional offerings rather than modular software products, with each service addressing specific marine infrastructure needs in both smaller and larger dimensions.

Differentiator

Problem solved

Functional benefit

Products and services

• Betongarbete (Concrete Work) Specialized underwater and marine concrete construction services for piers, harbors, bridge foundations, power stations, dam installations, and lighthouses, including Competency Class 1 concrete placement with underwater casting capabilities. Targeted at government, municipal, utility, and industrial clients requiring in-water concrete structures.
• Bryggor & småbåtshamnar (Piers & Small Boat Harbors) Sales and installation of fixed and floating piers, Y-boats, repair and maintenance services, chain and buoy stone replacement, and underwater inspections for marinas and small boat harbors. Targeted at marina operators, recreational harbor owners, and small commercial harbors.
• Bubbelgardin (Bubble Curtain) Custom-designed bubble curtain systems using perforated pipes with bottom weights that release compressed air to reduce underwater sound during noisy work (e.g., blasting, sheet piling), to act as protective barriers against sediment spread during dredging, and to keep harbors and marinas ice-free. Targeted at construction sites, harbor operators, and dredging projects.
• Inspektion (Inspection) Underwater inspection services for marine-laid pipelines and cables, concrete and steel structures such as bridges and quay installations, and hulls and propulsion systems on boats and vessels. Targeted at infrastructure owners, utilities, and vessel operators for preventive maintenance to detect deficiencies and avoid costly failures.
• PE-svetsning (PE Welding) Welding services for PE and other common thermoplastics, including butt welding of pipes, welding of pre-insulated pipes, electro-socket welding of pipes and fittings, and wire and extrusion welding, certified according to EN 13067, EWF 581-01, and Norwegian Nemko. Targeted at pipeline, district heating, and water infrastructure projects requiring certified welding.
• Siltgardin (Silt Curtain) Custom-designed silt curtains consisting of a floating body with hanging geotextile and bottom weights, primarily used to prevent spread of turbid bottom sediment during dredging work. Targeted at dredging contractors, harbor authorities, and environmental protection projects.
• Sjökabel (Marine Cable) Installation services for submarine cables including fiber optic cables and power cables, offering cost-effective solutions with minimal impact on existing infrastructure. Targeted at telecom operators, power grid owners, and utilities requiring subsea cable crossings.
• Sjöledning (Marine Pipeline) Installation of marine-laid water and sewage pipelines, intake and outlet pipes, and low-pressure pipes for applications such as stormwater and network expansion, including a proprietary method for heavily loaded (>100%) pipelines. Targeted at municipal water/wastewater utilities, energy companies, and industrial clients.

Quantifiable outcome

• Subsea pipelines can be installed at competitive prices compared to other installation methods while minimally affecting other infrastructure during and after construction.
• +2 more outcomes

Named customers5 records

Segments4 records

Ideal customer profiles4 records

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.

• Bro Underhåll & Service ABminorStrategic or Co-development Partner · 1 January 2021SEA was engaged as a subcontractor/supplier for specific underwater works on the Tottnäsbron renovation project where Bro Underhåll & Service AB was the main contractor for Trafikverket. SEA provided silt curtain installation, bubble system for ice-free water, Oxy-Arc cutting, UV welding, and marine transport services.

Scale indicators5 records

Recent moves4 records

Expansion highlights4 records

Broad incumbents

• NCC: Major Swedish construction and infrastructure contractor with civil engineering and marine adjacency. Targets government and infrastructure clients similar to SEA-Marine's blue-chip accounts like Trafikverket.
• Peab: Large Swedish construction group with civil engineering and infrastructure divisions. Undertakes harbor, bridge, and marine-adjacent infrastructure work in the Nordic market overlapping with SEA-Marine's customer segments.
• Boskalis Westminster: Global dredging and marine services major active in port and harbor infrastructure, subsea cable and pipeline installation. Represents a larger-scale competitor in adjacent categories to SEA-Marine's service portfolio.
• Veidekke Entreprenad: Major Norwegian/Swedish contractor with civil engineering and infrastructure capabilities, including road, bridge, and water infrastructure adjacent to SEA-Marine's marine construction focus.
• Skanska: Sweden's largest construction company with a substantial civil engineering portfolio that includes marine, bridge, and harbor infrastructure. Competes with SEA-Marine in larger totalentreprenad contracts while SEA-Marine serves as their underwater specialist subcontractor.
• Van Oord: Dutch marine contractor with dredging, subsea cable/pipeline installation, and harbor construction capabilities. Directly relevant for international subsea pipeline projects at scale similar to SEA-Marine's Väsbyviken 3km pipeline.
• Jan De Nul Group: Belgian marine and civil contractor specializing in dredging, subsea cable installation, and maritime infrastructure. A larger international counterpart to SEA-Marine for subsea cables and pipeline work.

Regional players

• Norwegian Maritime Group members (e.g., AF Gruppen Marine): Norwegian contractor with marine and subsea capabilities that compete for Nordic infrastructure tenders, including subsea cable and pipeline installation relevant to SEA-Marine's service lines.

Emerging players

• Marin & Hamn (Swerock/Svevia): Swedish contractors (including Svevia and others within the CRH/Swerock group) operating in marine and harbor construction, road, and water infrastructure with overlapping capabilities to SEA-Marine's specialized portfolio.

Direct peers

• Aarsleff (Per Aarsleff Holding): Danish specialist contractor focused on marine foundations, piling, and underwater infrastructure. Operates in the Nordic region with similar specialized underwater construction capabilities to SEA-Marine.

Market position

Strengths5 records

Weaknesses5 records

Competitive moat4 records

Key risks6 records

Key highlights7 records

Customer concentration

• Facebookfacebook.com/seasjoentreprenad
• LinkedInlinkedin.com/company/sea-sjoentreprenad

Compliance3 records

Revenue estimate

Valuation estimate

Number of profiles

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 SEA-Marine