In 2005, Turcas signed a Joint Venture Agreement with the Shell Company of Turkey Ltd. (Shell Turkey) for retail and commercial sales, marketing and distribution of fuel products and lubricants. Shell & Turcas Petrol A.Ş. (STAŞ), in which Turcas has a 30% stake, commenced operations on July 1, 2006. Additionally, Shell is a partner of Anadolu Tasfiyehanesi Inc., which is the only private petroleum refinery in Turkey jointly owned by Turcas (5%) and Shell & Turcas Petrol A.Ş.
In 2013, Turcas signed a partnership agreement with one of the leading energy companies in Germany, RWE for establishment and operation of a power plant. Denizli Natural Gas Fired Combined Cycle Power Plant, with total investment cost of EUR 600 million, has 800 MW installed capacity.
Another partner of Turcas in Anadolu Tasfiyehanesi A.Ş., BP is the only partner of Shell & Turcas Petrol A.Ş., which has a 50% share of Çekisan Storage Services Ltd. which is based in Istanbul and commenced operations in 1993 and a 50% share of Ambarlı Storage Services Ltd. which is based in İstanbul and commenced operations in 1995.
TOTAL Turkey, which was purchased by Demirören Petrol in 2016 is the only partner of Shell & Turcas Petrol A.Ş. (50%) in Samsun Fuel Storage A.Ş. (SADAŞ), which commenced operations in 2008, and has a share of 50%.
Petrol Ofisi A.Ş. is a partner of Shell & Turcas Petrol A.Ş. (50%) in Marmara Storage Services A.Ş., which commenced operations in 2011, and has a share of 50 %.
In 2006, Turcas founded SOCAR & Turcas Energy (STEAŞ) as a joint venture with the State Oil Company of Azerbaijan Republic (SOCAR) and in May 2008, STEAŞ won the Petkim Petrochemicals Holding A.Ş. privatization tender and acquired 51% stake in Petkim. STEAŞ established a 100% owned SPV in 2008, SOCAR & Turcas Refinery (STRAŞ) and obtained the all necessary permissions by the end of 2010. As of December, 2011, Turcas, transferred its 25% shares in STEAŞ to SOCAR, while purchasing 18.5% of the shares of SOCAR & Turcas Refining (STRAŞ), who is undertaking the SOCAR & Turcas Aegean Refinery Investment through Turcas Refinery Investments, its 99.6% subsidiary, from STEAŞ. Title of "SOCAR & Turcas Refining (STRAŞ)", which is on 18.5% subsidiary of Turcas Refinery Investments, was changed to "STAR Refining" on January 2, 2012. Turcas, which provided a great deal of contribution to development of this project, sold its 18.5% stake to SOCAR due to the excessive costs and decided to exit this incestment in May, 2014.
In 2007, Turcas established a joint venture with German E.ON company, one of the largest energy companies in the world for establishment and operation of a power plant. This partnership lasted until E.ON decided to exit Turkey in 2009.
In 2006, Turcas signed a joint venture agreement with the Spanish Iberdrola S.A. in order to bid in tenders for privatization of electricity distribution companies.
Conoco, which became a partner of Tabaş in 1995, became a 25% partner of Turcas after Tabaş purchased Turcas in the following year. This partnership lasted until the merger of Conoco and Phillips and decided to exit Turkey in 2004. Conoco’s stake in Turcas Petrol was purchased by Aksoy Holding in 2005.
Exxonmobil, has 15% stake in Çekisan Storage Services Ltd. in which Shell & Turcas Petrol has a 50% stake.
The first important international collaboration of Turcas was established by signing an agreement with the UK based Burmah Castrol in lubricants sector in 1954; this collaboration turned in to a partnership in 1988.