This dataset includes data from a tracking study, where 48 Atlantic salmon kelts were tagged with acoustic transmitters containing pressure sensors (Lotek MM-M-11-28-PM [76kHz], 12 × 65 mm length; Lotek Wireless Inc., Newmarket, ON, Canada) as well as simulated hydraulic data from computational fluid dynamics modelling. The data was collected in 2016 on the River Orkla, central Norway, just upstream of the Bjørset Dam. The data has been used to understand the swimming behaviours of the tagged kelts in an anthropogenically altered flow field (i.e., the area closest to the dam). The dataset is an xlsx file with two sheets. The first sheet, "Tracking data", contains the positions and timestamps for each detection of each kelt. The second sheet, "Hydraulic data", contains the streamwise velocity (Vx), transverse velocity (Vy), vertical velocity (Vz), and turbulence kinetic energy (k) for each position. Note, the hydraulic data was simulated under three different operational scenarios, as the operation at the hydropower plant changed over the course of the study period. When 's' = 2, this is the simulated hydraulic data just after the hydropower plant spillway opened (discharge via spillway = 8.0 m3/s), when 's' = 3 this is the discharge when the spillway opens further (22.3 m3/s), and 's' = 4 when it is opened to its furthest extent (38.4 m3/s). Variables in spreadsheets tag: this is the unique ID number for an individual kelt top: this is the timestamp for a given detection x: this is the kelt's longitudinal position, given in UTM y: this is the kelt's latitudinal position, given in UTM z: this is the kelt's depth, given in metres below the surface body_length: this is the kelt's body length, measured upon capture, in mm s: this refers to the operational scenario that the hydraulic data was simulated for Vx: this is the streamwise velocity, measured in m/s Vy: this is the transverse velocity, measured in m/s Vz: this is the vertical velocity, measured in m/s k: this is the turbulence kinetic energy, measured in m2/s2