On January 28, 2018, Sofia subway marks the 20th anniversary of the commissioning of its first section between the stations "Slivnitsa" and "Konstantin Velichkov". On this day, in 1998, the first train of the Metropolitan Underground Railroad pulled off on a subway route, which was 6,4 km long with 5 stations.

The construction of the first 5 stations began in 1979, when the first ground-breaking of the “Vardar” Station was made. A month later started the construction of "Lyulin". In 1980 and 1983 followed “Zapaden Park” and "Slivnitsa". The last ground-breaking was made for “K. Velichkov” Station in 1985. Construction of the subway depot began in 1978. The construction of the first 5 stations took 19 years.

Twenty years after the historic first trip on an underground train on the newly built 6.4 km section from r.a. "Lyulin" to "Konstantin Velichkov" Blvd., Sofia subway already has a built route of 40 km, a two-line network with 35 stations, and its share in the public transport system reached 34%. While the construction of the first 10 km until 2003 took 24 years, for the last 10 years were built 30 km of a total of 40 km. The speed of subway construction raised from the initial 380 m per year for the period 1979 - 2003 to 3.1 km in the last 10 years, thanks mainly to the inclusion of sites for European funding and local co-financing. More than half of the subway lines have been built in recent years.

The opening of Line 2 with 11 new stations in 2012 and the excellent train traffic organization made it possible to halve the traffic intervals on Line 1from 6 to 3 minutes in peak hours. The number of passengers has increased significantly and nearly 350 000 people ride the subway every day. Due to the higher speed, with the subway passengers save more than 110 000 hours a day.

Apart from being a large scale and complex transportation project, the subway is the largest environmental project in the capital. It has proven that in the areas it passes through, people tend to get off their cars and enjoy the convenience and speed of the underground railway. With the construction of Line 1 and Line 2, the number of passenger cars in circulation in Sofia reduced by about 55 thousand cars per day. With the construction of Line 3, traffic is expected to decrease by about 20 percent in the areas of its route. Overall, after the launch of Line 3, the environmental impact of the subway will reach reduction in emissions by about 90 thousand tons per year.

The subway is also a project that significantly changes people's living conditions and the quality of the urban environment. Upon completion of the underground railway facilities, new modern boulevards are being constructed on the surface, the status of the adjacent territories changes and modern planning and landscape of the areas appear.

Regardless of what has been achieved over the past two decades and the fact that it has become one of Sofia's success symbols and has entered the top 10 of the best infrastructure projects in Europe, the Sofia subway continues to develop. In recent years, the EC has repeatedly given its implementation for a good example. The new Green Line 3 is being built with the support of the European Regional Development Fund and local co-financing. The construction of stage 1 of the third metro-diameter was the first major Bulgarian project approved for funding by the European Commission for the programming period 2014-2020. Nearly EUR 400 million is the value of the new 12 kilometers of the third subway line, along with 20 new subway trains and the depot l in Zemliyane, which are funded under OP "Transport and Transport Infrastructure".

The most difficult central section of the new Line 3 - from “Vladimir Vazov” Blvd. to district “Krasno Selo”, is already built at 50% for 2 years from the beginning of its construction. It is 8 km long with 8 stations and is built in extremely complex geological and hydrogeological conditions. Plans are at the end of January 2018, the tunnel-boring machine, which digs the tunnels in the section, to be in the station at Alexandrovska Hospital. The length of the tunnel dug so far is about 2.6 km. By the end-of-year, the machine should reach the stop at Little City Theatre "Off the Channel".

The second stage of Line 3, including the construction of 4 km and 4 stations from district "Krasno Selo" through district “Ovcha Kupel” to the Ring Road, which started in June 2017, is completed at 12%. When Line 3 is ready at the end of 2019, it will connect two of the key transportation routes in Sofia – “Vladimir Vazov” Blvd. and the Ring Road with the Central Railway Station and the Airport. There will be a joint railway station on the Sofia-Pernik line via the metro station to district "Gorna Banya". By modern trains "Siemens" new 130 000 passengers will travel every day, and the total number of passengers on the subway will become nearly half a million.

The future plans of Sofia Municipality for the development of Line 3 and subway network in Sofia include priority continuation of the third beam from "Vladimir Vazov" Blvd. to road Botevgradsko shose, with new 3 km and 3 stations and extension to "Slatina" district and "Tsarigradsko shose" Blvd., with 5.6 km and 6 stations, as well as extension of Line 1 and Line 2.