After construction started in 1878 the 63 km long Neumarkt-Sankt Veit–Pocking section was opened on 1 September 1879 as a Sekundärbahn (secondary line).

Following the approval of its extension eastwards in 1884, the second, 35 km long, section from Pocking to Passau was completed in the years 1887 and 1888.

Once the route from Pocking to Kößlarn was opened on 1 December 1914 it offered a direct linkt to Simbach am Inn.

But tourist traffic to the Lower Bavarian "spa triangle" (Niederbayerisches Bäderdreieck increased its importance again despite the unfavourable routing of the line.

On 1 September 1979 the line's centenary was remembered in Pfarrkirchen with special celebrations, not least as a protest against possible plans for closure.

The halt at Eggenfelden Mitte was rebuilt nearer the centre of the town, those at Bad Höhenstadt, Neukirchen am Inn and Passau-Neustift were modernised.

Moreover, Sulzbach am Inn, Ruhstorf an der Rott and Engertsham will also be refurbished, for which a further 100,000 euros has been set aside.

The SüdostBayernBahn is therefore seeking to protect the unsupervised road crossings increasingly with flashing lights and barriers.

On 14 August 2008 two motor scooter riders were struck by trains at different places on the line and killed.