The original route of Reichsstraße 303 ran from Schweinfurt via Schonungen, Hofheim in Unterfranken, Coburg, Mitwitz, Kronach and Selbitz to Hof and continued via Rehau and Eger to Mitterteich.

In the early 1950s the road from Marktrodach via Stadtsteinach, Bad Berneck, Marktredwitz and Arzberg to Schirnding was redefined as the Bundesstraße 303.

From the 1960s to the 1990s the route was re-routed eastwards in stages over a length of 49.7 km and, as a result, it now only passes through Oberelldorf and Tambach.

Since 19 October 2007, the B 303 has crossed over junction 10 of the new A 73 autobahn (Nürnberg – Suhl) near Ebersdorf bei Coburg.

However these plans were not put into action due to the expected environmental damage, high construction costs and decreasing traffic volumes since January 2009.