Rantanen, who started for the Lappeen Riento, ran his first World Cup individual race in March 1986 in Lahti , which he finished in 26th place over 15 km freestyle. At the Nordic World Ski Championships in Lahti in 1989 , he finished 21st over 15 km classic. In the 1989/90 season he took 15th place in the pursuit in Lahti, in Reit im Winkl with tenth place over 30 km freestyle and in Val di Fiemme , with ninth place over 30 km classic, his only World Cup points and achieved thus the 30th place in the overall World Cup. In his only Olympic participation in February 1992 in Albertville , he came in 38th place over 30 km classic. He completed his 11th and last individual World Cup race that same month in Lahti, which he finished classically in 30th place over 15 km.
Finland