From Irkutsk taxi to Irkutsk airport, fly to Novosibirsk airport, then bus to Novosibirsk. 3 h 9 min $128. From Irkutsk Passajirskij train to Novosibirsk(RUS). 30 h 58 min $62. From Irkutsk drive to Novosibirsk. 26 h 41 min $137.
IrAero, Angara Airlines and S7 Airlines fly from Irkutsk to Novosibirsk twice daily. Alternatively, Russian Railways (RZhD) operates a train from Irkutsk to Novosibirsk twice daily. Tickets cost $35 - $90 and the journey takes 30 h 58 min.