1964 Obayashi Corp. began business activities in Thailand under the leadership of Shoji Shigeno. Commencement of construction of AlA Bldg. The first use of a protection sheet to prevent accidents in Thailand was widely acclaimed.
1966 Award of construction work of SEATO Headquarters and Japanese Embassy in Thailand.
1967 Dusit Thani Hotel project, a renowned landmark on Silom Road, started.
1968 Kenjiro Yoshino assumed directorship of Bangkok Representative Office.
1970 Completion of Sumitomo Thaniya Building as Thai Obayashi Corp., Ltd. 's Head Office.
1971 The largest projects completed were Toyota Motor Thailand, National Thai and Yakult (Thailand) factories.
1972 Major Projects completed were ESSO Building, West German Embassy, Royal Bangkok Sports Club and huge Chulaphon Dam for EGAT.
1974 Establishment of Thai Obayashi with Sommai Hoontrakool inaugurated as first chairman and Tadanao Murakami as President.
1977 Began sending Thai Obayashi staff annually for training at Obayashi in Japan. Sukeyoshi Morishita appointed Thai Obayashi president. Main woks of this year were MWWA Water tunnel and pump facility and factorires for Thai Suzuki Motor and Thai Otsuka Pharmaceutical.
1980 This year's main project was the Bangkok Bank Head Office, introducing Thai Obayashi's unique "OWS System" to Thailand.
1982 Suthasnradnakorn inaugurated as new Thai Obayashi Chairman and lehiro Matsui as President.
1984 10th Anniversary of Thai Obayashi Corp., Ltd. Construction of Minebea Thai, Ayutthaya factory, etc.
1986 Construction of Minebea Thai, Bangpa-in bearing & printer plants, etc.
1989 Sommai Hoontrakool reassumed Chairmanship of Thai Obayashi and Shigeo Takanashi was appointed President.
1991 Construction completed on Nantawan Bldg, Ratchadamri as Thai Obayashi's new Head Office.
1995 The Bangkok's latest remarkable construction, the Siam Commercial Bank Head Office (SCB Park Plaza) at Ratchayothin was completed this year.
1997 Major projects completed were Tripetch lsuzu Sales Service Center, Siam Discovery,Siam Tower, etc. Economic crisis. Depreciation of Thai Currency
2000 ISO 9001 certification for Thai Obayashi's Quality Management System. Completion of 4 major branches of hyper market, the Tesco Lotus in Bangkok, etc.
1981 Thai Obayashi finished Official Residence of the Japanese Ambassador to Thailand and Obayashi completed Youth Welfare Center and Rice Seed Storage Laboratory Center.
2001 Major projects completed were the 5 stars JW Marriott Phuket Resort and Spa, Shinawatra University (a new international University of Thailand in Pathumtani), etc.
2003 Sompong Chintawongvanich appointed as the first Thai President. Completion of Thailand's first underground subway MRT Chaloem Retchanongkhon line. Also, the construction of Suvarnabhumi Airport, Bangkok's second international airport was under progress as per plans.
2004 30th Anniversary of Thai Obayashi Corp., Ltd. and 40th Anniversary of Obayashi Corporation since the first establishment in Thailand.
2005 Major project completed was Siam Paragon, a remarkable world class shopping center in the heart of Bangkok.
2006 The Royal Occasion of the 60th anniversary of HM the King's accession to the throne. Major projects were The Boromratchasathit Maholan Throne Hall, Toyota Banpho Plant with total floor area 223,000 sq.m. completed within 10 months and The Embassy of Japan.
2008 Major projects completed were Marriott Timeshare Phuket Ph-Ill. Anantara Resort Phuket. ISO 14001 - certification for Environmental Management System. Economic flop in USA knows as Hamburger Crisis.
2010 Major projects completed was BU Landmark.
2011 OHSAS 18001 certification for Occupational Health & Safety management system. Sompong Chintawongvanich, the first Non-Japanese Officer appointed as Executive Officer of Obayashi Corporation (Japan). Major projects completed include St. Regis Bangkok and Park Ventures Ecoplex.