The biggest achievements in the club's history are two second-place finishes in the Swiss Cup (1955 and 2019), as well as reaching the group stages of the 2005–06 UEFA Champions League.

At the end of the 1953–54 season, the team finished in second place only behind FC Lugano and was promoted to the first division, the Nationalliga A (now known as the Swiss Super League), for the first time in the club's history.

Under his management, Thun was promoted to the Nationalliga A after 47 years of absence from the Swiss top flight at the end of the 2001–02 season.

They started their campaign on 14 September 2005 away at Arsenal, where after equalising through Nelson Ferreira, they narrowly lost 2–1 after Dennis Bergkamp scored in the match's final seconds.

[citation needed] Thun's 1–0 victory thanks to Selver Hodžić's 80th-minute winner propelled them into second place in the group.

Despite his success, coach Urs Schönenberger was regarded as a controversial figure by the club management because of his uncompromising nature and communication style.

[1] Just three days prior to their Uefa Cup tie against Hamburger SV, on 13 February 2006, Thun sacked Schönenberger, who had guided them to the Champions' League group stages and replaced him with Heinz Peischl.

However, Hamburg was too strong at their home, the Volksparkstadion, and managed to overturn the deficit, winning the second leg 2–0 (2–1 on aggregate).

[2] Urs Fischer took over management of the team in January 2013 and lead FC Thun to a fifth-place finish in the 2012–13 season.

[5] Thun finished the 2019–20 season in second to last place and had to face the runners-up team of the 2019–20 Challenge League, FC Vaduz, in the relegation play-offs.

Gabriel Kyeremateng finished the season as the third highest goalscorer (16) and was nominated for March's player of the month award.

[16] FC Thun made 11 signings in the off-season, including Declan Frith who had played for both Aston Villa and Chelsea academy sides in England, Ashvin Balaruban from Neuchâtel Xamax, Fabio Fehr from FC Vaduz and Genis Montolio who previously played for Villarreal in La Liga.

[20][21] In July, FC Thun launched their new home shirts manufactured by Macron and sponsored by Visana.

[25] FC Thun were drawn away in the first round of the 2024–25 Swiss Cup against SC Schwyz who qualified under the Suva Fairplay Trophy rules.

In 1998, to celebrate the 100th anniversary of the club's formation, FC Thun used a logo with the name script in black, on a background showing the number 100 in red and yellow.

[33] Note: Flags indicate national team as defined under FIFA eligibility rules; some limited exceptions apply.