The St Helena Tunnel is a twin-tube road tunnel that forms part of the Pacific Highway in the Byron Bay hinterland in New South Wales, Australia.

The 434-metre-long (1,424 ft) tunnel under St Helena Hill in Ewingsdale was built as part of the 17-kilometre (11 mi) Tintenbar to Ewingsdale upgrade, which involved a new alignment of the highway.

The tunnel was built to avoid the steep grades of St Helena Hill on the previous alignment of the highway, and the associated heavy truck noise and pollution.

[1] The cost of the Tintenbar–Ewingsdale upgrade project was $862 million, jointly funded by the Federal and New South Wales governments.

[2] The St Helena Road passes over the top of the tunnel and provides local access to the Bangalow Road (B62) that is a link between Bangalow and Byron Bay.