The present disclosure pertains to a bike trailer (1) comprising a main frame (2). The main frame (2) comprising a lower frame portion (3), a rear frame portion (4) and two side frame portions (5,6) provided on opposite lateral sides of the lower frame portion (3), the main frame (2) defining an accommodation space (7) for a passenger. The bike trailer (1) has an extension in a longitudinal direction (L), in a transverse direction (T) and in a height direction (H) and the bike trailer (1) comprises a seat structure (9) forming a seating area for the passenger. The seat structure (9) comprises a seat back (9a) and a seat bottom (9b), the seat back (9a) being configured for releasable connection to the bike trailer (1) in a first position (P1) and in a second position (P2), the first position (P1) providing a first lateral seating area for the passenger, and the second position (P2) providing a centralized seating area for the passenger, as seen in the transverse direction (T). The present disclosure also pertains to a bike trailer (1) comprising a main frame (2), the main frame (2) comprising a lower frame portion (3), a rear frame portion (4) and two side frame portions (5,6) provided on opposite lateral sides of the lower frame portion (3), the main frame (2) defining an accommodation space (7) for a passenger. The bike trailer (1) has an extension in a longitudinal direction (L), in a transverse direction (T) and in a height direction (H). The rear frame portion (4) comprises an upper cross bar (8) extending between the two side frame portions (5,6), the bike trailer (1) comprising a seat structure (9) forming a seating area for a passenger, the seat structure (9) comprising a seat back (9a) and a seat bottom (9b), the seat back (9a) being configured for moving between an upright position and a reclined position, the seat back (9a) being connected to the cross bar (8) at an upper end section (10) of the seat back (9a) via a reclining member (15), the reclining member (15) being transferable between a first configuration (C1) wherein the seat back (9a) is in the upright position and a second configuration (C2) wherein the seat back (9a) is in the reclined position, and wherein the upper end section (10) of the seat back (9a) is provided with a greater distance from the cross bar (8) in the second configuration (C2) than in the first configuration (C1).