If you rent a pontoon boat, be careful.
1.) If moving never just shut off the motor suddenly, water stops a boat pretty quickly. If you do this the front of the boat will generally go under, not sink, just go under. Ask jdarg.
2.) Anchor the boat out a little way from the beach and walk to the beach, if you park it on the beach you may have a beached boat when the tide goes out. Seatow charges a small fortune for to pull the boat back in the water. If you choose to wait the rental place will call the coast guard if you're not back within about 20-30 minutes of the agreed upon time.
3.) It's tempting, but it's also illegal, to feed the dolphins. Unfortunately they have been trained to congregate for free food at the mouth of the pass. You can enjoy the show, but do not feed or touch them. If you want to swim with dolphins you need to go over to Gulf World and pay for that, you get a cute picture too.