The Long Beach Branch is an electrified LIRR branch that connects the City of Long Beach, on Long Beach Island, a barrier island in the Atlantic Ocean with New York City. Long Beach with its station on Long Beach Island is the only LIRR station not on the Island of Long Island other than Manhattan Island’s Penn Station. This branch runs for 6.9 of its own miles from just after Valley Stream where the Atlantic Branch ends and the Far Rockaway Branch splits off to the south. 5.4 of these miles are after the line leaves the elevated right-of-way used by the Babylon branch to head south on a two-track line with grade-crossings, with a short single tracked section where trains cross over Reynolds Channel on a single track movable bridge to enter the Long Beach terminus station with a 10 track card, and 4 tracks that platform.

Service on the line operates every hour or better with off-peak service to and from Penn Station stopping normally at Woodside. A few rush hour trains (in both directions) operate to and from Atlantic Terminal. A schedule quirk of the LIRR means Long Beach Branch Trains provide all hourly service to and from the eastern Queens stations of Laurelton, Rosedale, and Locust Manor (which are on the Atlantic Branch and on the Far Rockaway Branch timetable) on Saturdays and Sundays, offering these customers a one-seat weekend ride into Penn Station. Weekday service to these stations is almost exclusively served by the Far Rockaway Branch with all non-rush hour trains going to Atlantic Terminal.