Tel Aviv is located right by the sea, so of course there are many different beaches there. Different people like different beaches, and the beaches are not all the same. Here is a summary of some of the most popular beaches in Tel Aviv:
Gordon Beach, a rather touristy beach which is full of tourists especially during the summer months, since many hotels are located here. You can play volleyball and also work out here, since there are free gym machines right on the beach.
Metzitzim beach is the one closest to the harbor and all the coffee shops there, so it is also rather touristy, but much less crowded that Gordon beach. Has a really nice beach bar too.
There is a segregated beach for religious people close to Metzitzim beach as well.
The Hilton beach is a hangout place for sexual minorities and also allows dogs to enter.
The Dolphinarium beach has a lot of activities, such as martial arts and other sports that you can take part in. Much less crowded than most of the other beaches, due to it being rather far south.
Frishman beach is another rather touristy beach, but fun if you want to look at people, since EVERYONE comes here! Has several nice beach bars too.