The writing on the back of the undated postcard says: "This pier is at the end of 12th St. & upper stairs is a dancing pavilion. Downstairs all sorts of stores and boat landings - boats leave every 1/2 hour for ocean beach (1/2 hour ride 15 cents each way). Can come back by auto over longest modern bridge in the world 3 miles long, same price. Here is where everyone goes to bathe, can't bathe in Bay. We took the (undecipherable) it was fine. Hope you will have some idea of city from cards I sent. I thought St. Pete was pretty but after seeing Miami I would never go back there, from what I hear things are no higher here. I have a large room, 2 windows, hot and cold water in room, & a private bath room toilet and tub, $1.50 per night."
The 12th Street referred to in the first sentence was later renamed to Flagler Street when the streets were renumbered. See http://www.pbase.com/donboyd/image/77197923 to view a map of the old street numbering system.
The 3 mile long bridge mentioned had to be the Collins Bridge also shown on the map linked to above.
This postcard was published by J. N. Chamberlain, Miami, Fla. C. T. American Art is also printed on the back of the card.