German Railways (DB) operates a train from Regensburg to Füssen hourly. Tickets cost $35 - $55 and the journey takes 1 h 31 min. 2 other operators also service this route. Alternatively, FlixBus operates a bus from Regensburg to Füssen 5 times a week. Tickets cost $15 - $26 and the journey takes 3 h 40 min. FlixBus also services this route 5 times a week.
From Regensburg Hbf train to München Hbf Gl.27-36, train to Buchloe, then train to Füssen. 4 h 9 min 61€. From Regensburg, Regensburg central station bus to Memmingen, Memmingen central bus station then bus to Füssen, Füssen, Kemptener Str.. 5 h 40 min 26€. From Regensburg drive to Füssen. 2 h 34 min 32€.