The Hayling Island branch was a railway in Hampshire, England, that connected Havant with Hayling Island. It was sometimes known as the Hayling Billy, a name now given to the footpath along the old track.
The line was opened by the London, Brighton and South Coast Railway (LBSCR) for goods on 19 January 1865, and for passengers on 16 July 1867. It ran from Havant to Hayling Island station. There were two intermediate stations at Langston (sic) and North Hayling. Neither were ever "halts", in spite of their small size.
The line itself was mainly used during the summer months as people from the South Coast would travel down to the beach on Hayling Island. The coaches would often be overflowing during these months, however would be virtually empty during the winter, which would become a problem.
The LBSCR quickly ran into difficulty during the construction of the railway, as they had attempted to save on the cost of buying land on Hayling Island for the line by constructing an embankment on the mud flats in the sheltered waters of Langstone Harbour—This was an ambitious plan, which also involved the construction of wet and dry docks at Sinah Lake. Though they were given a grant to the mudlands by William Padwick, who was himself behind the plan, and the promoters offered to build the embankment and Railway at a cost of £80,000, the area was not sheltered as had been hoped: the bank was severely eroded before the railway could be completed.
The board of trade inspector was invited to certify the line as being fit for passenger traffic, but he initially refused to do so as he found that many of the sleepers had begun to rot in the original section of the railway, and there was also an unauthorised level crossing at Langstone. The former problem was quickly fixed but the level crossing remained until the closure of the line.