St. Pete and the greater Tampa Bay area are well known for their many popular beaches. Living in St. Pete, you'll almost be surrounded by nice beaches, so finding a St. Pete apartment close to a beach isn't going to be too difficult. The real question you ask yourself here should be: How close do I want my St. Pete apartment to be to the beach?
If you live in a St. Pete apartment, you are living on an inlet, so you are surrounded by water on three sides. Happily, St. Pete is well connected to downtown Tampa both by land and also by both the 275 bridge and the Gandy Bridge. Even though you have tons of waterfront property, you won't be limited by only having one way back in or out.
Most of the popular west coast beaches in St. Pete are not technically a part of St. Petersburg but they are close enough that I am including them here. Madeira Beach is just west of where St. Pete becomes Seminole. South of Madeira you will find Treasure Island and then St. Pete Beach. These areas are great if you are really wanting to live right on a Gulf Coast beach. The limitation of these areas is that they are very desirable areas to live in, and they are reached by a few bridges, which do get backed up at certain times of the day.
Along the tip of St. Pete, neighborhoods such as Pinellas Point and Gulfport offer nice apartments near St. Pete beaches. Living near Northshore puts you close to a popular beach along Tampa Bay. The Northshore beach offers a playground, a year-round olypic swimming pool, tennis courts, and plenty of parking. If you really want a view of the water, Coquina Key, Snell Island, and Tropical Shores might be good neighborhoods for you to check out.
Honestly, if you live in St. Pete, you can't be too far from a beach, but some areas will obviously put you much closer. Living closer to or on the beach does give you a chance to go every day, but you may find that you are content only going once a week or so. Additionally, the closer you are to the water, the more expensive your rent will be. Living right on the beach also puts you more at risk of flooding if a hurricane comes through.
That said, living on the beach can be amazing. You can fall asleep and wake up to the sound of the waves hitting the beach. You can take a walk on the beach the same way most people take a walk around their neighborhood. If you forget to bring something with you to the beach – no worries, just run back and get it! Living in a St. Pete apartment by the beach can really be an amazing experience.