What Penta-Ocean does

Penta-Ocean Construction Co., Ltd. (五洋建設株式会社) is a major Japanese general construction company whose primary operating footprint is marine and port construction, civil engineering, and building construction. The company serves national and local government agencies responsible for port facilities, harbor infrastructure, and coastal protection, as well as private sector clients in energy and commercial construction. Its Technical Research Institute (技術研究所), located in Nasushiobara City, Tochigi Prefecture, operates five specialized facilities — main building, hydraulic experiment building, structural experiment building, multipurpose experiment building, and outdoor yard — and functions as the R&D engine for the parent.

The company's technology portfolio centers on marine and port construction, structural engineering, concrete technology, hydraulic engineering, and seismic isolation. Proprietary developments include the PC compression joint precast pier method (developed jointly with Nihon PS, PARI, and Tokyo University of Science), hollow super-large PCa member rapid pier construction, calcium silicate modified soil (NETIS CBK-150001-VR), and the Seed Log Filter for turbid water treatment (NETIS KT-230052-A). AI-based anomaly detection for RC structures, a spherical projectile pier underside sound inspection system, and behavior-associated infection risk visualization technology represent recent applied innovations in inspection robotics and computer vision.

The business model is project-based construction contracting with government and private sector clients via direct sales and competitive bidding. Revenue is generated from one-time construction contracts; pricing is project-specific and not publicly disclosed. Geographic scope is domestic Japan. The Technical Research Institute drives technology credibility through academic publication (1,300+ papers in civil and architectural engineering as of March 2026), academic conference presentations, NETIS and performance certifications, and joint research with Japanese universities and engineering firms.

Name

Penta-Ocean

Legal name

PENTA-OCEAN CONSTRUCTION CO.,LTD. (五洋建設株式会社)

Website

https://penta-ocean-int.com

Company type

Private

Operating status

Operating

Headcount range

1–10 employees

Short description

Penta-Ocean Construction Co., Ltd. (五洋建設株式会社) is a major Japanese general contractor specializing in marine, port, and harbor construction, civil engineering, and building construction for government agencies and private sector clients, with proprietary precast concrete, AI-based infrastructure inspection, and seismic isolation technologies developed through its Tochigi-based Technical Research Institute.

Ownership category

akta.pro rank

Product category

Construction Engineering

NAICS

Structural Steel and Precast Concrete Contractors (23812), Ship Building and Repairing (336611), Engineering Services (541330), Search, Detection, Navigation, Guidance, Aeronautical, and Nautical System and Instrument Manufacturing (334511)

SIC

Heavy Construction Other Than Bldg Const - Contractors (1600), Construction - Special Trade Contractors (1700), Ship & Boat Building & Repairing (3730)

akta.pro primary industry

Marine Piling & Deep Foundations (Jetties, Dolphins, Moorings) (IMAFAJAE)

akta.pro secondary industries

Marine Terminals & Cargo Handling Infrastructure (RoRo, Bulk, Container) (IMAFAJAF), Underwater Inspection, Maintenance & Repair (UWILD, Diving/ROV, In-water Cleaning) (IMAJAFAJ), Marine & Offshore Wind BOP Construction (Foundations, Cables, Ports, Installation Support) (EUAMAFAI), Production Design & Detailed Engineering (3D CAD, Drawings, BOM, Nesting) (IMAJAGAK)

Keywords

• Marine construction
• Port infrastructure
• Civil engineering
• Offshore wind foundations
• Precast concrete construction

Headquarters

HQ city

Nasushiobara City

HQ country

Japan

HQ region

Asia

Offices1 record

Markets served

GTM type

B2B

Offering type

Services

Cost components

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

Revenue model

1. Construction Services: General construction services including marine/port construction, building construction, civil engineering works. Projects for government agencies (port/harbor, infrastructure) and private sector clients.

Go-to-market motion1 record

Distribution channels2 records

Marketing channels4 records

Core offering

Penta-Ocean Construction Co., Ltd. (五洋建設株式会社) is a major Japanese construction company specializing in marine and port construction, civil engineering, and building construction for government agencies and private sector clients throughout Japan. The company operates a Technical Research Institute in Nasushiobara City, Tochigi Prefecture, with five specialized testing facilities that research and develop proprietary construction technologies including precast concrete pier methods, AI-based structural inspection systems, seismic isolation technology, offshore wind foundations, and BIM/CIM-based construction information systems. The institute publishes technical yearbooks, peer-reviewed papers, and maintains NETIS registrations for its proprietary technologies.

Product overview

Penta-Ocean Construction's Technical Research Institute develops advanced construction and civil engineering technologies. The portfolio includes seismic isolation technologies, precast concrete construction methods (PC圧着接合工法), AI-powered infrastructure inspection systems, underwater inspection robotics, and VR-based safety training solutions. Research spans hydraulic/marine engineering, geotechnical engineering, structural engineering, materials science, and environmental technologies, supported by specialized testing facilities including hydraulic laboratories, structural testing buildings, and multi-purpose experimental halls.

Differentiator

Problem solved

Functional benefit

Products and services

• Marine and Port Construction Services General construction services for port and harbor infrastructure including pier construction, breakwater construction, dredging, and coastal protection works for national and local government agencies as well as private sector energy and industrial clients in Japan.
• Civil Engineering and Building Construction Services General civil engineering works and building construction services for private sector clients including energy facilities, commercial buildings, and industrial facilities in Japan.
• PC Compression Joint Precast Pier Method Full-precast pier construction technology where all major pier components are factory-manufactured and assembled on-site with prestress introduction using PC compression joints. Enables significant construction period reduction and cost reduction for port and energy facility piers.
• AI-Based RC Structure Anomaly Detection System AI-based system that uses automatic measurement robots with small vibrators to apply micro-vibrations to RC structures, with machine learning analyzing response data to detect internal anomalies. Provides objective and quantitative structural evaluation replacing expert-dependent inspection methods. Co-developed with Tohoku University and Oita National College of Technology.
• Spherical Projectile Pier Underside Sound Inspection System Unmanned small boat system that launches metal spheres via compressed air at pier concrete surfaces, with sound wave analysis to detect concrete delamination. Eliminates requirement for worker entry into narrow, harsh underwater pier environments for inspection.
• VR Construction Safety Education System VR-based construction safety education system providing immersive experiences including backhoe operation simulation and hazard awareness training. Includes 3D tsunami simulation experiences for disaster preparedness education.
• i-PentaCOL BIM/CIM Construction Information System BIM/CIM-based construction progress reporting system using building information modeling and database integration for automated reporting on construction projects. Netis-registered technology.
• Offshore Wind Monopile Foundation Construction Offshore wind turbine monopile foundation engineering including seismic isolation technology, water-damping plates, and hydrodynamic analysis for renewable energy infrastructure in marine environments.
• Behavior-Based Infection Risk Visualization Technology Camera-based technology that estimates and visualizes contamination levels on furniture surfaces in real-time based on detected user behavior data. Color-coded visualization helps cleaning staff identify priority areas. Developed in collaboration with AIREX.

Quantifiable outcome

• Significant construction period and cost reduction through hollow super-large PCa members
• +3 more outcomes

Segments3 records

Ideal customer profiles3 records

Technology focussed No

API detail

Has API

No

API docs

API detail

Core technology

AI maturity

App detail

AI capability8 records

Feature7 records

Partnerships

Eight partnerships are on record, tiered core and minor.

• 共和技研株式会社 (Kyowa Giken Co., Ltd.)coreStrategic or Co-development PartnerJointly developed the sphere launching and recovery device for pier underside sound inspection system. Kyowa Giken contributed to the mechanical system for unmanned boat-based compressed air sphere launching and sound capture technology.
• 東京都立大学 (Tokyo Metropolitan University)coreStrategic or Co-development PartnerAcademic partner in joint development of sphere launching/recovery system for pier inspection. Contributed research expertise to sound analysis algorithms and concrete delamination detection methodology.
• 株式会社日本ピーエス (Nihon PS Co., Ltd.)coreStrategic or Co-development PartnerJointly developed PC compression joint precast pier construction method. Nihon PS contributed precast construction expertise and manufacturing capabilities for full-precast pier components.
• 国立研究開発法人海上・港湾・航空技術研究所 港湾空港技術研究所 (PARI)coreStrategic or Co-development PartnerJoint research partner for PC compression joint precast pier method. Contributed harbor/port engineering research expertise and technical validation.
• 東京科学大学 (Tokyo University of Science)coreStrategic or Co-development PartnerAcademic partner in multiple joint developments including PC compression joint method and hollow super-large PCa member construction technology. Contributed advanced structural engineering research.
• 東北大学 (Tohoku University)coreStrategic or Co-development PartnerCo-authored award-winning AI/data science paper on machine learning-based anomaly detection in concrete structures. Contributed AI/machine learning research expertise.
• 大分工業高等専門学校 (Oita National College of Technology)coreStrategic or Co-development PartnerCo-authored AI/data science paper award on concrete structure anomaly detection. Contributed technical research collaboration on AI applications in civil engineering.
• AIREXminorStrategic or Co-development PartnerTechnical collaboration partner for behavior-associated infection risk visualization technology research. Contributed to technology development and validation.

Scale indicators4 records

Recent moves6 records

Expansion highlights5 records

Direct peers

• Toa Corporation: Toa Corporation (東亜建設工業) is a Tokyo-listed Japanese construction firm with deep specialization in marine, port, and harbor civil engineering — the most direct peer to Penta-Ocean's core marine construction franchise. Both compete for the same government port-authority contracts.
• Maeda Corporation: Maeda Corporation (前田建設工業) is a Japanese construction firm active in civil engineering, marine works, and precast concrete methods. Its portfolio of infrastructure and marine projects competes with Penta-Ocean for both government and private sector civil engineering contracts.
• Toyo Construction: Toyo Construction (東洋建設) is a Japanese mid-tier contractor focused on marine civil works, reclamation, and port/harbor infrastructure. It overlaps almost exactly with Penta-Ocean on marine piling, breakwater construction, and coastal engineering projects.
• Nishimatsu Construction: Nishimatsu Construction (西松建設) is a long-established Japanese general contractor with significant marine, tunneling, and civil engineering operations. Its marine and port construction practice competes head-to-head with Penta-Ocean on public-sector tenders.

Emerging players

• Oriental Shiraishi Corporation: Oriental Shiraishi (オリエンタル白石) is a Japan-listed specialist in precast and prestressed concrete bridge and pier construction. Its core technology stack directly overlaps with Penta-Ocean's PC compression joint precast pier method and represents the most direct specialist competitor in precast marine infrastructure.

Broad incumbents

• Shimizu Corporation: Shimizu (清水建設) is a top-tier Japanese super general constructor with significant marine, civil, and building operations. Its broader geographic reach and substantially larger R&D budget make it a broad incumbent against which Penta-Ocean competes on larger and more complex tenders.
• Toda Corporation: Toda Corporation (戸田建設) is a major Japanese general contractor with civil engineering and marine construction operations. It is comparable to Penta-Ocean in civil works but operates at larger scale and with broader portfolio, including building construction.
• Obayashi Corporation: Obayashi (大林組) is a leading Japanese super general constructor with deep civil engineering, marine construction, and offshore capabilities. Its scale, diversification, and innovation roadmap place it as a broad incumbent peer across much of Penta-Ocean's addressable market.
• Kajima Corporation: Kajima (鹿島建設) is one of Japan's "super general constructors" with vast civil, building, and international operations. Its marine and port division competes with Penta-Ocean on large-scale government tenders while its much larger balance sheet and R&D base pose a long-term competitive threat.
• Hazama Ando Corporation: Hazama Ando (安藤ハザマ) is a Japanese general contractor formed from the merger of Hazama and Ando, with active civil engineering, building, and energy-sector construction practices. It overlaps with Penta-Ocean on infrastructure and energy facility construction projects.

Market position

Strengths5 records

Weaknesses5 records

Competitive moat4 records

Key risks6 records

Key highlights7 records

Customer concentration

• LinkedInlinkedin.com/company/penta-ocean

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 Penta-Ocean