ScotRail operates a train from Glasgow to Dumbarton Castle every 15 minutes. Tickets cost $6 - $8 and the journey takes 33 min. Alternatively, First operates a bus from Glasgow to Dumbarton Castle every 20 minutes. Tickets cost $3 - $5 and the journey takes 50 min.
From Glasgow Queen Street Low Level train to Dumbarton East. 33 min £4. From Glasgow, Argyle Street (Radisson Hotel) line 1 bus to Dumbarton, Leven Street (Knoxland Primary School). 50 min £2. From Glasgow Queen Street Low Level night train to Dumbarton Central. 27 min £13. From Glasgow taxi to Dumbarton Castle. 24 min £27. From Glasgow drive to Dumbarton Castle. 24 min £2.