The Saundersfoot Railway's coastal branch connected the Stepaside colliery/ironworks with the harbour at Saundersfoot, running through the town centre and three short tunnels. The first horse-drawn train ran on 1st March 1842 with closure claiming the line in February 1939, by which time steam locomotives were plying their trade.
The south tunnel, around 73 yards in length, is masonry lined except for a short section near its centre. The middle tunnel - by far the shortest at ~18 yards - punches through a rock outcrop and also benefits from a neat masonry lining. A short distance along the trackbed is the longer north tunnel, measuring around 111 yards. This features a lining towards its ends but the section in-between is exposed rock although occasional masonry supporting columns have been added.
All three now form part of the Pembrokeshire Coast Path. The north tunnel has enjoyed a fair amount of repair work to ensure its continued suitability for that purpose.