how are the beaches in Japan?

How are most beaches in japan like? especially in the osaka and tokyo areas? how clean are they?Are most open to the public?
Last and not least how is the water?

Beaches near the cities here are, as you might imagine, not the nicest. They tend to be very crowded in summer, and around Tokyo in particular the water is not so clear, partly due to the quality of the sand, which is quite grey and silty.

100km out of Tokyo the beaches can get nicer- the beaches of southern Izu Peninsula are a good example. It depends on the area though- even away from the big cities, some areasare more industrial/concreted over than others.

but are they open to the public?

Of course they are- that's why they are crowded with people in summer!

sorry bout that becuase there are a lot of beaches in mexico that are private and only open to pep ole at the hotels which kinda pisses me off.
(btw the private hotel beaches they are also crowded but by rich tourist)

There are very few "real" beach resort hotels in Japan.

In tropical Okinawa there are several authentic beach resort hotels with private beaches, but most beaches in Japan are not worth building large resport hotels and therefore are open to the public during the safe swimming season which is during July and August.

Actually, in Tokyo there is only one swimming beach (Odaiba), and I wouldn't swim there if I were you. People in Tokyo usually make day-trips to Hayama in Kanagawa Prefecture or spend the night at Izu or Boso Peninsulas.

Btw, I notice that even in Mexico, the pretty beaches are private but the ugly beaches are open to the public. That's how it goes.

Thank you very much to the people that have given me information on this subject it was greatly appreciated

http://www.nanki-shirahama.com/eng/kankou.htm

Kamakura is a short train ride from Tokyo and has a large sandy public beach. If it's a nice day you could split the day with visits to Kamakura's temples and an afternoon at the beach. When I was there it was fairly clean and reminded me of a Southern Calif beach. The surfers were wearing wetsuits though (it was October) so I figured the water was cold.
http://www.japan-guide.com/e/e2166.html

anyone know a good beach to take a girl to? like a couples beach or more romantic setting?

I'm surfer and I go to surfing at mid winter too. If you can take a car and want to avoid the crowded, Chiba(Kujyuukuri-sotobou) is better, and if you go to more south area around Kamogawa, the beach is even clean. You can get there from Tokyo at day trip.
But not all area is allowed swimming. Please be careful.