塞普泰姆夫里索菲亚

Early ages

On November 5, 1944 the clubs Sportclub Sofia, Sokol and Vazrazhdane unite under the name of FC Septemvri Sofia; the name derives from the revolution of September 1944. On March 26, 1945, the additional clubs of Botev (Konyovitsa), Ustrem (Zaharna fabrika), Pobeda (Krasna Polyana), and Svoboda (Tri kladentsi) merge into the club. In May 1948, the club, then playing in the 1st Sofia Division, is briefly merged with second-division CDV/Chavdar (Sofia) and the unified club wins the 1948 Bulgarian Championship by overcoming Levski Sofia in the final.

Septemvri starts the 1948–49 season in the newly formed A Republican Football Group, but only six months later is separated from CDV (Chavdar) and removed from the division, with the current title given to CDNV, Chavdar's new name, which would ultimately become CSKA Sofia. At the end of the 1948–49 season, Septemvri is allowed to take part in a two-match play-off for entering first division against Marek Dupnitsa. After both matches end with a 2:0 win for each team, a third game is played in which Septemvri falls 1:0 and remains in second division.

From 1949 to 1969, Septemvri exists as an independent club, during which period it reaches the height of its success. In 1959, the club finishes first in the B PFG and is promoted to first division for the 1959–60 season. That same season, Septemvri finishes in 5th place and claims the Bulgarian Cup after a dramatic 4:3 win over Lokomotiv Sofia in extra time. The club's stay among the elite lasts only two years, as in 1961 it is relegated to the B PFG, where it remains until 1968.

In 1969, during another period of football reform in Bulgaria, Septemvri was again merged into CSKA Sofia. This unification continued for almost 20 years, until 1988, when the club became independent again and joined the V AFG. In 1993, Septemvri won a promotion to the B PFG. In 1998, the club became the champion of the B PFG and joined the elite for the first time since 1961. It finished in 16th place and was relegated again.

2000s

During the 2000–01 season, the club finished in 13th place in the B PFG and was relegated to the V AFG, where it remained until 2008. In March 2008, the club was heavily penalized after a scandalous match against FC Bansko, when coach Rumen Stoyanov ordered his players to leave the field, a serious offence according to Bulgarian Football Union regulations. With an executive decision, the BFU removed Septemvri from the V AFG and placed it in the A OFG, the Sofia Regional Football Group. Despite this setback, the club attained 1st place in the division in the 2008–09 season and qualified for a play-off match for entering the V AFG against FC Novi Iskar. After an emotional 0–0 in regular time, penalty kicks were in order to determine the team going forward. Septemvri lost the penalty shootout 5–4.

Chandarov era (2015–present)

Merge with DIT academy and Pirin Razlog (2015–2017)

In 2015, Rumen Chandarov, owner of DIT Sport Academy, one of the best Bulgarian football academies in the last few years, announced that he is the new owner of Septemvri, with the goal of getting the young players to compete in the First Professional Football League of Bulgaria. The team merged with Conegliano German and started the 2015–16 season from V Group. Nikolay Mitov was appointed as a manager of the team. In the end of the 2015 it was decided that the team will give a bigger chance to their U19 players, so most of the players who joined in the season start left and only seven players left, but 18 players joined from the U19 team which was third in the Elite Youth Group by the end of 2015. Some media announced that Chandarov will stop financing the team also due to the fact that he started financing Botev Plovdiv, but Chandarov said that this is not true and the only reason to do this is to make youth players enter the men's football.

On 24 June 2016, Pirin Razlog merged into PFC Septemvri Sofia. From the new season 2016–17 Septemvri will compete in the new Second League, the second division of Bulgarian football. Septemvri also returned in the Bulgarian Cup and drew the Bulgarian First League team Beroe Stara Zagora. They won the match on 21 September 2016 with 2–0, goals scored by Georgi Stoichkov and Petar Tonchev. The team finished their season in Second League in 2nd place, two points behind the winners of the group — Etar and qualified for the Promotion playoffs against elite member Montana. The team won the playoff on 3 June 2017 with a 2–1 final result and returned to the top level after 19 years.

Return to Professional leagues (2017–present)

On 8 June 2017, Dimitar Vasev was announced as the manager who would lead the team in their return to the First League with Hristo Arangelov, the caretaker manager after Nikolay Mitov, as his first assistant. The team announced that they would play to Vasil Levski National Stadium until their Septemvri Stadium is built. Later, the club owner Rumen Chandarov revealed that the team would play at Bistritsa Stadium after the stadium gained a First League licence, since he didn't want Septemvri to play in front of empty seats. Septemvri's first match was against Dunav Ruse on 17 July and the team lost the match 0–2. Week later Septemvri won their second match against Pirin with Boris Galchev scoring the winning goal. After four defeats in five games, Vasev was released and Nikolay Mitov returned in charge after his release from Levski Sofia. Septemvri finished the half season in 10th place with 23 points after a 2–1 win over Cherno More.

On 20 February 2018, Septemvri's executive director Georgi Markov died aged 46, three years after he suffered a heart attack.

Septemvri secured their place in First League on 15 April 2018 after a 0–2 win over Dunav Ruse and qualified for European play-off quarter-finals.

Septemvri could not avoid relegation in the next season, however, as they were relegated after losing in the relegation playoffs to FC Arda Kardzhali , 0-1. This ended their two year stay in the Bulgarian elite.

Back in the second tier after two seasons in the elite, Septemvri managed to maintain their good form and remained largely within the top three in the Second League, a strong candidate for promotion. The 2019-20 season was eventually not finished, due to the COVID-19 outbreak in Bulgaria. The last matches were played in early March. At that time, Septemvri was second in the league, three points behind CSKA 1948. Septemvri faced the 13th placed team from the First League in a promotion playoff, but lost. On 5 May 2022, after a great second half of season 2021-22, Septemvri secured their return to First League. This achievement was accomplished under the management of Slavko Matić. Septemvri only managed to make a cameo appearance in the elite, suffering immediate relegation back to the Second League for season 2023–24.