Born in Frauenfeld, Frei started his youth football with local amateur club FC Frauenfeld and then he moved to the youth of FC Winterthur in summer 2000. However, he came through the ranks with FC Basel, joining their youth department and playing in their U-16 team, winning the Swiss championship title for that age group in the 2004–05 season. He played in their U-18 team during the 2005–06 season, under coach Patrick Rahmen and his assistant Marco Walker and with them won both the Swiss U-18 championship and the U-19/18 national cup that season.[4] For the 2006–07 season, he advanced to their U-21 team, who played in the third tier, and was given a professional contract.[5] The team won their division and became Swiss champions at U-21 level, Frei, playing as attacking midfielder, made 30 appearances, scoring 11 goals.[6]
Ahead of their 2007–08 season Frei was called into the first team squad by head coach Christian Gross.[7] After having played in 13 test games, Frei played his domestic league debut for the club in the home game in the St. Jakob-Park on 22 July 2007 as Basel won 1–0 against Zürich.[8] He played his UEFA Cup debut with the team in the home game on 16 August, coming on as substitute, as Basel won 2–1 against SV Mattersburg.[9] Basel played in the 2007–08 UEFA Cup. Winning both matches in the qualification round and both matches in the play-off round, they team advanced to the group stage, which they ended undefeated in second position, after playing 1–0 at home against Stade Rennes, 0–0 away against Dinamo Zagreb, 1–0 at home against Brann and 1–1 away against Hamburger SV, to continue the knockout stage. But then they were eliminated here by Sporting CP. Frei had seven appearances during the teams 10 European games.[10] At the end of their 2007–08 season Frei won the Double with the club. They won the League Championship title with four points advantage over second placed Young Boys. Frei had 24 appearances.[11] In the Swiss Cup Basel advanced to the final, and winning this 4–1 against AC Bellinzona they won the competition.[12]
To the beginning of the 2008–09 season he was member of the Basel team that won the Uhrencup. They beat Legia Warsaw 6–1 and played a 2–2 draw with Borussia Dortmund to end the table on top slot above Dortmund and Luzern.[13] Frei played his UEFA Champions League debut for Basel on 26 November 2008 in the 5–0 away defeat against Shakhtar Donetsk.[14] He scored his first goal with the team in the home game on 4 December 2008. It was the last goal of the match as Basel won 3–1 against FC Aarau.[15]
In July 2009, due to the fact that Basel strengthened their squad for the beginning of the 2009–10 Swiss Super League season, Basel's new trainer Thorsten Fink loaned Fabian Frei to FC St. Gallen. During his two-year loan in St. Gallen, he played 64 league games in which he scored 13 goals.
For the start of the 2011–12 Swiss Super League season he was recalled to Basel, the reigning Swiss Champions, and he immediately won his place in the starting eleven. Frei scored his first Champions League goal for Basel on 14 September 2011 in the Group C 2–1 home win against Oțelul Galați,[16] his second on 27 September in the 3–3 draw at Old Trafford against Manchester United[17] and his third on 22 November in the Arena Națională, in Bucharest, as Basel won the away game against Oțelul Galați 3–2.[18] At the end of the 2011–12 season, Frei won the Double, the League Championship title[19] and the Swiss Cup[20] with Basel.
At the end of the 2013–14 Super League season Frei won his fourth league championship with Basel.[24] They also reached the final of the 2013–14 Swiss Cup, but were beaten 2–0 by Zürich after extra time. During the 2013–14 Champions League season Basel reached the group stage and finished the group in third position. Thus they qualified for Europa League knockout phase and here they advanced as far as the quarter-finals. In their season 2013–14 Basel played a total of 68 matches (36 Swiss League fixtures, 6 Swiss Cup, 6 Champions League and 10 Europa League and 10 test matches). Frei totaled 66 appearances, 34 League, 6 Cup, 6 Champions League and 10 Europa League as well all 10 in the test games.[25]
The season 2014–15 was a very successful one for Basel and for Frei. The championship was won for the sixth time in a row that season[26] and in the 2014–15 Swiss Cup they reached the final. But for the third season in a row, they finished as runners-up, losing 0–3 to FC Sion in the final. Basel entered the Champions League in the group stage and reached the knockout phase as on 9 December 2014 they managed a 1–1 draw at Anfield against Liverpool.[27] Frei scored the goal for FC Basel against Liverpool to help Basel to the next round of the UEFA Champions League. But then Basel then lost to FC Porto in the Round of 16. Basel played a total of 65 matches (36 Swiss League fixtures, 6 Swiss Cup, 8 Champions League and 15 test matches). Under trainer Paulo Sousa Frei totaled 56 appearances, 31 in the Super League, 5 Cup, 8 Champions League, as well 12 in test games. He scored a total of 4 goals in these matches.[28]
On 23 December 2017, FC Basel announced that Frei would return to the club, signing a four-and-a-half-year contract dated up until June 2022.[30]
Under trainer Marcel Koller Basel won the Swiss Cup in the 2018–19 season. In the first round Basel beat Montlingen 3–0, in the second round Echallens Région 7–2 and in the round of 16 Winterthur 1–0. In the quarter-finals Sion were defeated 4–2 after extra time and in the semi-finals Zürich were defeated 3–1. All these games were played away from home. The final was held on 19 May 2019 in the Stade de Suisse Wankdorf Bern against Thun. Striker Albian Ajeti scored the first goal, Fabian Frei the second for Basel, then Dejan Sorgić netted a goal for Thun, but the result was 2–1 for Basel.[31] Frei played in five cup games and scored not only in the final but also a goal in the match against Echallens.
International career
Frei represented Switzerland at various age levels. He played his Swiss Under-16s debut on 12 October 2004 in the 3–1 away win against the Belgium Under-16s. In 14 games for the Switzerland U-17 team he scored ten goals.
^ abcFC Basel 1893 (2006). "Zwei weitere Titel für FCB-Nachwuchs" [Two more titles for FCB youngsters] (in Swiss High German). FC Basel 1893. Archived from the original on 30 December 2013. Retrieved 18 June 2006.{{cite web}}: CS1 maint: numeric names: authors list (link)
^Garin, Erik; Stokkermans, Karel (2018). "Switzerland 2007/08". Rec.Sport.Soccer Statistics Foundation. Retrieved 16 November 2023.
^Swiss Football Verband (SFV) (6 April 2008). "AC Bellinzona - FC Basel 1:4 (0:1)". Swiss Football Verband (SFV) internet site. Retrieved 16 November 2023.