What Keihin Dock does

Keihin Dock Co., Ltd. (京浜ドック株式会社) is a privately held Japanese small-vessel shipbuilder and ship repair company founded in 1968 with investment from Nippon Yusen Kaisha (NYK Line) and operating as a wholly owned subsidiary within the NYK Group. Headquartered in Yokohama with two manufacturing facilities — Koyasu Factory and Oppama Factory (opened 2003) in Yokosuka — the company operates three divisions: Ship Repair (the original 1968 business), New Shipbuilding, and Environmental Business. Its product portfolio centers on tag boats (tugboats), patrol vessels, disaster prevention vessels, and a growing line of next-generation low-emission and autonomous vessels.

The company's technical credentials are anchored in a sequence of decarbonization firsts: Japan's first LNG-fueled tag boat "Sakigake" (2015), which was converted into the world's first commercial ammonia-fueled tag boat delivered in August 2024; Japan's first domestically manufactured fully battery-electric work vessel "e-Crea" launched May 2025; an electric propulsion tag boat under construction; and a joint USV (Unmanned Surface Vehicle) mass-production program with Oceanic Constellations announced October 2025. The company also holds MLIT certification under the Maritime Industries Strengthening Law (No. 49, December 2025), qualifying it for government subsidies, tax incentives, and national shipbuilding support over a five-year period.

Keihin Dock's go-to-market is B2B enterprise field sales targeting Japanese domestic maritime shipping operators (tugboat operators such as Shinnihon Kaiyo, Naikai Tugboat, Akita Tugboat), government agencies (METI for disaster prevention vessels, Japan Maritime Self-Defense Force for YT-series tugs), and NYK Group subsidiaries. Revenue is generated through one-time project contracts — new vessel construction and repair services priced on a project basis. In October 2025, the company completed an organizational integration with Yokohama Machinery Co., Ltd. (founded 1978) to consolidate technical sales and engineering capabilities. The firm employs 51–100 people.

Name

Keihin Dock

Legal name

京浜ドック株式会社

Website

https://keihindock.co.jp

Company type

Private

Founded year

1968

Operating status

Operating

Headcount range

51–100 employees

Short description

Keihin Dock is a privately held Japanese small-vessel shipbuilder and repairer, founded 1968 and wholly owned by NYK Group, building tugboats, disaster prevention vessels, and pioneering ammonia-fuel and battery-electric vessels for Japanese maritime operators and government agencies.

Ownership category

akta.pro rank

Product category

Shipbuilding and Ship Repair

NAICS

Ship Building and Repairing (336611), Ship and Boat Building (3366)

SIC

Ship & Boat Building & Repairing (3730)

akta.pro primary industry

Pilot Boats & Crew Transfer/Service Craft (Pilotage, CTV-style workboats) (IMAJADAG)

akta.pro secondary industry

Dry Docking & Dockyard Operations (Graving/Floating Docks, Docking Services) (TLAHAMAA)

Keywords

• Ship repair services
• Small vessel construction
• Tugboat shipbuilding
• Disaster prevention vessels
• Maritime decarbonization vessels

Headquarters

HQ city

Yokohama

HQ country

Japan

HQ region

Asia

Offices3 records

Markets served

GTM type

B2B

Offering type

Hardware or Manufacturing

Cost components

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

Revenue model

1. Ship Repair Services: Core business segment providing repair and maintenance services for small vessels, established in 1968 as the company's founding business with NYK Group backing.
2. New Shipbuilding: New construction of tag boats, patrol vessels, disaster prevention ships, and specialized vessels. The company has built Japan's first hybrid propulsion system vessel, first LNG fuel tag boat, and continues innovation in next-generation vessels.
3. Environmental Business: Environmental-related services and products, including drainage treatment equipment and other eco-friendly maritime solutions.

Go-to-market motion1 record

Distribution channels1 record

Marketing channels3 records

Core offering

Keihin Dock is a shipbuilder and ship repair company that constructs new small vessels (tag boats, disaster prevention vessels, defense vessels, and next-generation eco-friendly vessels) and provides repair/maintenance services for small vessels. The company operates two shipyards in Kanagawa Prefecture and is recognized for pioneering alternative fuel vessels including the world's first ammonia fuel tag boat and Japan's first battery-electric work vessel.

Product overview

Keihin Dock is a Japanese shipbuilding and ship repair company operating three core divisions: Ship Repair, New Shipbuilding, and Environmental Business. The company's flagship products include tag boats, disaster prevention vessels, and next-generation eco-friendly vessels. Notable achievements include the world's first ammonia fuel tag boat 'Kizuna', Japan's first battery-powered electric work vessel 'e-Crea', and ongoing development of electric propulsion tag boats and USV (Unmanned Surface Vehicle) mass production systems for ocean monitoring. The company operates two manufacturing facilities: Koyasu Factory and Oppama Factory in Kanagawa Prefecture, and became part of Nippon Yusen (NYK) Group upon its founding in 1968.

Differentiator

Problem solved

Functional benefit

Products and services

• Ship Repair Services (修繕部門) Ship repair and maintenance services for small vessels, established in 1968 as the company's original business division. Services are performed at company facilities with vessels brought to dock at the Koyasu Factory in Yokohama.
• New Shipbuilding (新造船部門) Construction of new vessels including tag boats, disaster prevention vessels, and next-generation fuel vessels. The division expanded into new shipbuilding in 2003 with the opening of Oppama Factory, enabling full-cycle vessel construction for Japanese maritime customers.
• Environmental Business (環境事業部門) Environmental business operations focused on contributing to maritime decarbonization and sustainability solutions, including drainage treatment equipment and eco-friendly maritime solutions across the company's three divisions.
• Ammonia Fuel Tag Boat 'Sakigake' (魁) — World's First Commercial Ammonia Fuel Vessel World's first commercial ammonia fuel tag boat, originally built as LNG fuel in 2015 and converted to ammonia fuel in 2024. The vessel is operated by NYK Group subsidiary Shinnihon Kaiyo and received the Ship of the Year 2024 Technical Special Award, marking a milestone in maritime decarbonization.
• Electric Work Vessel 'e-Crea' (エクレア) Japan's first domestically manufactured battery-powered fully electric work vessel, designed for zero-emission harbor and work operations. The name combines 'electric' and 'Crea' (creation), symbolizing a new era of vessels.
• Electric Propulsion Tag Boat Next-generation electric propulsion tag boat powered by lithium-ion batteries, featuring Japan's first domestically manufactured motor drive system. Developed in collaboration with Nippon Yusen for harbor assistance and tug operations with zero emissions at point of use.
• Tag Boats (タグボート) Tugboats for harbor assistance, cargo ship maneuvering, and maritime support operations. Keihin Dock has delivered multiple tag boats of varying horsepower (3,600-4,400 HP) to operators including Shinnihon Kaiyo, Akita Tugboat, Naikai Tugboat, Daito Corporation, Higashi-nihon Tag Boat, Wing Maritime Service, and Kashima Port.
• Disaster Prevention Vessels (防災船) Chemical firefighting and oil spill response vessels deployed at national oil stockpile bases across Japan. Recent deliveries include Chikabisanriku (2024, Iwate Prefecture/Kuji Base) and Chikashireimei (February 2025, Kagoshima Prefecture/Kushikino Base) for the Ministry of Economy, Trade and Industry.
• Defense Tugs (YT Series) for Japan Maritime Self-Defense Force Towage vessels built for Japan's Ministry of Defense and Japan Maritime Self-Defense Force under defense contracts. YT13 was assigned to Yokosuka District Force (December 2020) and YT14 to Sasebo District Force (March 2021), marking the company's first defense ministry projects.
• Unmanned Surface Vehicle (USV) Mass Production System Unmanned Surface Vehicle (USV) constellation program developed in partnership with Oceanic Constellations Co., Ltd. under the 'Sea Satellite Constellation' (海の衛生群) concept. The mass production system enables ocean monitoring, data collection, and communication network infrastructure for maritime operations.

Quantifiable outcome

• World's first commercial ammonia fuel ship - Ship of the Year 2024 Technical Special Award
• +2 more outcomes

Named customers13 records

Segments4 records

Ideal customer profiles3 records

Technology focussed No

API detail

Has API

No

API docs

API detail

Core technology

AI maturity

App detail

Feature5 records

Partnerships

Five partnerships are on record, tiered core and minor.

• Yokohama Machinery (株式会社横浜マシナリー)coreStrategic or Co-development Partner · 23 December 2025On October 1, 2025, Keihin Dock and Yokohama Machinery completed a business integration. Founded in 1978 as a specialized marine parts supplier, Yokohama Machinery had provided engine parts and supplies for approximately 47 years. The integration aims to consolidate technical sales capabilities and strengthen engineering business and sales force.
• MoonRakers Technologies (ムーンレイカーズテクノロジーズ株式会社)minorStrategic or Co-development Partner · 24 October 2025Collaboration with Toray spin-off venture to develop high-performance workwear for shipyard employees. The uniforms utilize advanced fiber technology (DTF printing) to reduce discomfort from heat, sweat, odors, and dirt, featuring designs including the blueprint of the world's first commercial ammonia fuel vessel Sakigake.
• Oceanic Constellations (オーシャニック・コンステレーションズ株式会社)coreStrategic or Co-development Partner · 23 October 2025Joint demonstration contract signed to develop Japan's first domestic mass production system for small Unmanned Surface Vehicles (USV). The partnership aims to build ocean monitoring and communication network infrastructure using USV constellation technology called '海の衛星群' (Sea Satellite Constellation).
• NYK Bulk-Project (NYKバルク・プロジェクト)minorChannel Partner/ Reseller/ DistributorNYK Bulk-Project has been providing regular shipping services to Fiji since 1981, representing a long-standing relationship between Japan and Fiji. Keihin Dock was visited by Fiji's Prime Minister Rabuka in November 2025 to inspect shipyards.
• Japan Coast GuardminorOthersJapan's first successful demonstration of USV automatic recovery capability by OC company, conducted with cooperation from maritime authorities.

Scale indicators3 records

Recent moves7 records

Expansion highlights6 records

Broad incumbents

• Damen Shipyards Group: Damen is a global leader in harbor and terminal tugboat construction with standardized series production across multiple geographies. It is a relevant broader incumbent peer for Keihin Dock's tugboat business, particularly as Japanese operators look to international builders for alternative-fuel harbor craft.
• Oshima Shipbuilding Co., Ltd. Oshima Shipbuilding is a Japanese shipbuilder focused on bulk carriers and selected working vessels. It is a broader incumbent with overlapping presence in the Japanese domestic shipbuilding market, though it operates at a meaningfully larger scale than Keihin Dock.
• IHI Corporation: IHI is a large Japanese industrial conglomerate with a shipbuilding and marine engineering division that produces tugboats, harbor vessels, and marine machinery. It is a broad incumbent that competes in some of Keihin Dock's segments but operates across a much wider industrial portfolio.
• Tsuneishi Shipbuilding Co., Ltd. Tsuneishi is a major Japanese and overseas shipbuilder producing bulk carriers, container ships, and selected smaller commercial vessels. It is a broader incumbent in Japanese shipbuilding with overlapping customer relationships among domestic shipping groups that also procure from Keihin Dock.
• Sanmar Shipyard: Sanmar is a leading Turkish builder of harbor tugboats with a global customer base. While geographically distant, it competes for the same tugboat operator procurement budgets as Keihin Dock and represents a key international alternative for harbor-assistance vessel tenders.
• Mitsui E&S Shipbuilding Co., Ltd. Mitsui E&S Shipbuilding is a major Japanese shipbuilder with capabilities spanning large commercial vessels through to smaller working craft. It represents a much larger incumbent that overlaps with Keihin Dock in tugboat and small-vessel construction but with substantially greater scale and capital resources.

Direct peers

• Hakata Shipbuilding Co., Ltd. Hakata Shipbuilding is a Japanese shipyard that specializes in the construction of harbor tugboats and small commercial vessels. It is a direct competitor to Keihin Dock in the Japanese small-vessel shipbuilding segment, particularly for harbor assistance craft.
• Kanasashi Heavy Industries Co., Ltd. Kanasashi Heavy Industries is a long-established Japanese shipyard that builds harbor tugboats and small commercial vessels. It directly overlaps with Keihin Dock in vessel class (tag boats/workboats) and serves many of the same Japanese tugboat operator customers.
• Asakawa Shipbuilding Co., Ltd. Asakawa Shipbuilding is a Japanese shipbuilder that constructs harbor tugboats and small workboats for domestic shipping companies. It competes with Keihin Dock in the same niche of small harbor-craft construction and shares a similar customer profile of Japanese tug operators.
• Imai Shipbuilding & Engineering Co., Ltd. Imai Shipbuilding is a Japanese mid-size shipyard that builds harbor tugboats and small working vessels for domestic operators. It is the most directly comparable domestic competitor to Keihin Dock in terms of vessel type, customer base (Japanese tugboat operators), and yard scale.

Market position

Strengths5 records

Weaknesses5 records

Competitive moat5 records

Key risks6 records

Key highlights7 records

Customer concentration

Revenue estimate

Valuation estimate

Number of profiles

Profiles6 records

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 Keihin Dock