Before the Isle of Wight lost almost all of its 50-odd miles of railways by the mid 1960s virtually every route touched the "seaside" at some point. There were stations at Freshwater, Cowes, Ryde (3), Yarmouth, Bembridge, Sandown, Shanklin and Ventnor (2) - that I can think of.
Being annoyingly pedantic here (but this thread is taking, in my opinion, a strict and severe line in the defining of "seaside" locations): I see something of a question-mark over whether Freshwater's station, when in operation, could legitimately rate as "seaside". It lay a little way beyond the landward end of the Western Yar estuary, which opens into the Solent at Yarmouth; and about three-quarters of a mile north of the Isle of Wight's southern coast. Present-day convention, 66 years after closure of the Newport -- Freshwater line, sees Freshwater "village" -- one of the built-up areas of this western end of the island, and which held the former Freshwater rail station -- as lying essentially, a short way inland: with the separate settlement of Freshwater Bay set to its south, and upon the small bay in the coastline, of that name.
Drifting somewhat topic-wise: not a rail route / journey, but a coast-to-coast undertaking within England which struck me as somewhat splendid when I travelled over part of its run, some years ago. This was the National Express coach route between Grimsby (perhaps not acceptable to participants in this thread as "seaside", the way neighbouring Cleethorpes is) and Westward Ho! -- I travelled by it from Birmingham to Bideford. Something which could never have been accomplished by rail: not even in the brief sixteen-year spell for which Westward Ho! was rail-served -- its line was physically isolated from the country-wide rail system.
