Trenitalia operates a train from Sanremo to Genoa Airport (GOA) every 3 hours. Tickets cost $9 - $21 and the journey takes 1 h 45 min. Alternatively, FlixBus operates a bus from Sanremo to Genoa Airport (GOA) 5 times a week. Tickets cost $9 - $15 and the journey takes 3 h 20 min. AMT Genova also services this route every 20 minutes.
From S.Remo train to Genova Sestri Ponente. 1 h 45 min 14€. From Sanremo bus to Genova - Doria Metro Principe then line 3 bus to Sestri Ponente - Via Angelo Siffredi. 3 h 53 min 13€. From Sanremo drive to Genoa Airport (GOA). 1 h 29 min 21€.