San Marino participated in the Eurovision Song Contest 2021 in Rotterdam, the Netherlands. The Sammarinese broadcaster San Marino RTV (SMRTV) internally selected Senhit as their representative with the song "Adrenalina" featuring Flo Rida. Senhit was due to compete in the 2020 contest with "Freaky!" before the event's eventual cancellation and had also served as the nation's entrant. "Adrenalina" was written and composed by Thomas Stengaard, Joy Deb, Linnea Deb, Jimmy Thörnfeldt, Kenny Silverdique, Suzi Pancenkov, Malou Linn Eloise Ruotsalainen and Chanel Tukia, along with Senhit and Flo Rida themselves. While Flo Rida had provided vocals for the track from its inception, his participation in the performance of the entry on the Eurovision stage was only confirmed on the day of the second semi-final due to travel restrictions related to COVID-19.