Parnell Tunnel, Railway tunnel in Parnell, Auckland, New Zealand.

Parnell Tunnel is a railway passage that runs beneath the suburb and features two separate portals for train operations. The newer double-track section currently handles rail traffic, while the older single-track section has been closed to rail service since 1930.

Construction of the original tunnel began in 1864 and was completed in 1873 after facing funding difficulties and ground slippages during excavation. The completion of the older tunnel marked an important step in Auckland's railway expansion.

The tunnel is a key part of how Auckland's neighborhoods developed and grew over time, linking communities through rail transport. Both tunnel portals remain visible landmarks that residents and visitors encounter when moving through the suburb.

The active double-track tunnel carries trains on the Newmarket Line between Newmarket and Waitematā, so it is seen from outside only; no public access into either bore. The old single-track portal, closed since after 1930, stands nearby and can be picked out at ground level. A proposal exists to reopen the old tunnel for pedestrians and cyclists, but it is not a route today.

During World War II, the original tunnel served as a shelter for local residents during air raids, revealing its importance beyond just moving trains. This secondary use demonstrates how the structure adapted to meet community needs during wartime.