An immersed-tube road tunnel, approeched by cut-and-cover sections and 1090m long overall, carries the A55 dual carriageway road (nprn 403728) under the River Conwy estuary between Conwy and Llandudno Junction as part of the Conwy bypass. The tunnel was built of pre-formed concrete sections which were floated out into the estuary and lowered into a prepared trench; it curves gently on plan. It was Britain's first immersed-tube road tunnel and was opened by the Queen on 25 October 1991. The tunnel superceded the 1958 Conwy Road Bridge (nprn 85483).
B.A.Malaws, RCAHMW, 25 February 2010.