[5] Born in Ishigaki, Okinawa Prefecture, Arashiro was the Japanese Under-23 National Time Trial and Road Race Champion in 2005.

[9] He completed his third Tour de France in 2012 in 84th place—the highest placing of a Japanese person at that time[10]—and earned the most combative award on Stage 4.

[11] He participated in the men's road race at the 2012 Summer Olympics and finished in 48th place.

[12] A few weeks after the Olympics, he became the first Japanese to win a race categorized as HC by the UCI, the Tour du Limousin of the Palais des Sports de Beaublanc in Limoges.

[13] Competing in the 2015 Vuelta a España,[14] he became the first Japanese person to finish the three Grand Tours.