The commercial opening of the section of the pipeline that passes through Serbia from the Bulgarian to the Hungarian border will be on Jan. 1.
Serbian President Aleksandar Vucic will attend the opening in Gospodjinci in the municipality of Zabalj.
The Serbian section, from Zajecar to Horgos, is about 403 kilometers (250 miles) long and delivers Russian gas through Turkey and Bulgaria. Its capacity is 15.75 billion cubic meters per year.
The 930-kilometer-long TurkStream pipeline will carry Russian gas under the Black Sea through Bulgaria, Serbia and Hungary, with another section reaching Turkey.
The project is the biggest-diameter offshore gas pipeline in the world laid at such depths with a capacity of 31.5 billion cubic meters per year.