UNITHAI SHIPYARD AND ENGINEERING LIMITED operates Thailand's largest shipyard, strategically located within the Laem Chabang deep-sea port — the country's principal international port. Incorporated in 1990 and operational since September 1993, the shipyard is developed on approximately 693,300 square metres of prime waterfront adjacent to the main port area. The facility is accessible via protected deep water, rail link, and a well-developed road network, positioned only two days' sailing from Singapore.

The shipyard provides a comprehensive range of maritime services including ship repair, modification, conversion, newbuilding, afloat repair, and heavy fabrication for the offshore oil and gas industry. The yard accommodates commercial and military vessels up to Suezmax and mini-cape class, with a maximum vessel length of 282 metres, beam of 47 metres, and draft of 8 metres. The offshore fabrication division delivers steel structures, topside modules, subsea stations, and jack-up rig components.

Unithai Shipyard maintains internationally recognized certifications including ASME U, U2 and R Stamp for pressure vessel design, EN 1090 structural steel certification, DIN EN ISO 3834-2 welding quality standards, and Class NK recognition for diesel engine repair. The yard employs approximately 2,000 staff.