How far is the nearest beach resort from New York using public transport.

Thank you.

Not sure what you mean by a "beach resort". If you are talking about a day trip for swimming and sun the closest beach is Coney Island using public transport. If you are talking about a hotel on the ocean to spend a few days you would have to go to the Jersey shore using NJ TRansit. There are probably some places on LOng Island (Fire Island) but I can't provide specifics.

If you want to day-trip from Manhattan, there is Jones Beach or also beaches at Fire Island that you can reach via LIRR. They have info on their website about how to do it (you buy a combo train ticket-beach pass).

If you want a "resort" to stay for more than a day, there are several options, depending on your standards of luxury. There is the Jersey shore (accessible by NJ Transit), Fire Island (accessible by train to ferry) or the Hamptons (accessible by train or Hampton Jitney bus). Each will have hotel or B&B-type accommodations. Of these, the Hamptons is the most luxurious with the most upscale accommodations (if that's what you mean by "resort").

Sorry

I did just mean for a day trip.

Angela,
Try Jones Beach on Long Island - less than an hour from Penn Station, via Long Island Railroad and bus. RT cost $11.00
You'll find beach info. at:
http://nysparks.state.ny.us/maps/
click on Long Island region and LIRR info at:
http://www.mta.nyc.ny.us/libus/jones_beach/jbcs.htm

Jones Beach opened in 1929, has 6.5 miles of ocean beach, 2 mile boardwalk, 2 swimming pools, pitch/putt golf, and the world's best (canned) Manhattan Clam Chowder - the sea breeze makes it taste better.
hth,