Sink or Swim is a BBC sitcom that aired on Thursday nights from 1980-1982.

Brothers Brian and Steve Webber attempts to strike out in business involves a soggy narrowboat and a dubious decision to ply the Thames-side tourist trade. Unfortunately, Steve is as loutish and lazy as Brian is charming and ambitious, and the latter finds both his enthusiasm and his relationship with idealistic girlfriend Sonia severely hampered by his brother's persistent presence.