Belmar is a small town and the main areas of interest — the beach, the boardwalk, Main Street, and the marina — are all walkable from each other. Once you are in town, a car is unnecessary.
Getting to Belmar is easiest by car from New York City or the rest of New Jersey. Take the Garden State Parkway to Exit 98 or the shore roads from Asbury Park or Point Pleasant. Parking on Ocean Avenue and the side streets fills up quickly on summer weekends; arrive early, or park further back on Main Street where spaces are more available.
By train, New Jersey Transit's North Jersey Coast Line stops at Belmar station on the corner of 10th Avenue. Trains run from New York Penn Station throughout the day, with the journey taking around 90 minutes. Service is more frequent in summer and around peak beach weekends. The station is a five-minute walk from the beach — this is one of the easier Jersey Shore towns to reach without a car. Check the NJ Transit website for current schedules.
Bicycles are practical on the flat streets and the boardwalk (allowed before 9am on the boardwalk). Several rental options are available near the beach access points in summer.