21st Beach attracts a family crowd because it is easier to visit than 7th Street Beach. A cute art deco snack shack (where you can buy fruity popsicles) stands at the entrance to the beach, as well as showers for washing off. There is a large parking lot that makes this beach much easier to visit than other sections of Miami Beach. You pay at machines with your credit card and the price is very reasonable. The water is just gorgeous here- crystal clear up close and a vibrant blue-green from a distance. Tiny waves break and it stays shallow for a long while. What a lovely swim!

Tons of people come here on the weekend with colorful beach umbrellas and sand toys. The wide, soft sandy beach allows plenty of room for everyone. Tall high-rises form the backdrop. Impressive cruise ships move in and out the harbor. Not all the beachgoers are uber-fashionable as expected- there are some families just enjoying a casual day at the beach. There are some ritzy girls walking around the cafes south of the beach though.
Enjoy some food at Free Spirits Sports Cafe, next to the beach beside the parking lot. You can soak up the beach vibe, sitting outside at the red picnic tables.
Afterwards, check out Ocean Drive near 7th Street to take in a wild scene! The beach at 7th Street is even more exciting than 21st Street Beach, with the gay beach just steps away at 12th Street and many tourists.
Collins Ave, parallel to Ocean Drive, has wonderful Art Deco architecture. Across Collins Ave from the beach is a large grassy area and the Bass Museum of Art, a very small stylish gallery with a very small collection and some interesting temporary exhibits. Spend half an hour inside enjoying the AC! There is also the Miami-Dade Library, which unfortunately has a very smelly crowd of homeless people. This building is built in Art Deco-style, as is the lovely Miami City Ballet building next door.
It's super fun to rent a bike from one of the Deco Bike stations and ride along the Miami Beach Boardwalk south all the way to South Pointe Park.
If you take the boardwalk north instead, you will come to 36th Street Beach, 46th Street Beach, 53rd Street Beach, 64th Street Beach, then Surfside Beach.
There are playgrounds with shade canopies at 46th Street Beach (Indian Beach Park), 53rd Street Beach (Beach View Park), and 64th Street Beach (Allison Park).

Directions

Exit Highway 95 at Highway 112/195 (this is exit number 4) and head toward the ocean for five miles. This is a beautiful drive across the causeway and over two bridges. Turn right on Indian Creek Rd. Turn left on 21st Street and park in the parking lot. You will need to pay at the machines with cash or credit card. Cost is $1.50 an hour- a bargain!
Besides the large parking lot at 21st and Collins Ave, there is also a small public parking lot a few blocks west at 21st St and Park Ave (behind the Bass Museum of Art). Two other parking lots are on 23rd St, one block west of Collins Ave on Liberty Ave.
Free Spirits Sports Cafe, 100 21st Street, Miami Beach, FL 33139, call (305) 532-5399.
Bass Museum of Art, 2100 Collins Ave, Miami Beach FL 33139, call (305) 673-7530. Open Wed-Sun 12-5. Admission is $8 per adult, and $6 for seniors and students. Kids under 6 may enter for free but would not enjoy anything hands-on here.

Click on map for interactive view