This dataset contains processed reflection seismic profiles from the southwestern Algarve shelf, Portugal. The profiles were recorded in January 2020 during a campaign onboard HSV FISÁLIA of the Portuguese Navy for project OnOff "Coupling onshore and offshore tsunami record: complementary tools for a broader perspective on tsunami events", funded by FCT (Portuguese Foundation for Science and Technology) grant PTDC/CTAGEO/28941/2017. The dataset compiles all reflection seismic profiles recorded with a centipede sparker source designed by RCMG at Gent University, Belgium, and a SIG single-channel streamer receiving unit. The center frequency of the signal was around 600 Hz, with a sampling frequency of 16 kHz, a shot interval of 0.5 s, and an approximate vertical resolution of ~50 cm. Basic post-processing included burst noise removal, amplitude correction, bandpass filtering, and top muting. The dataset contains processed data as Label_processed.sgy files with Label_pick.txt files for seafloor picks.