Irina Terentjeva won a silver medal in individual 10 km F event in the 2001 European Youth Championships (EYOF 2001) in Vuokatti, Finland. She won a bronze medal in the individual 5 km F event at the 2002 Junior World Championships in Schonach, Germany.
Terentjeva's best finish at the FIS U23 World Ski Championships was a 7th place in the individual 10 km F event in Tarvisio 2007.
Her best World Cup finish was 25th at a 10 km event in Finland in 2005. Terentjeva's best position at the individual event 15 km F at the Winter Universiade was a 4th place in Pragelato 2007.
Irina Terentjeva moved to Finland in 2010 and finished her skiing career in 2012.