I'm now a PADI-certified Open Water Diver - weee! I even saw a sea turtle, and have determined that in a previous life, I must have been some sort of water animal (as I am very comfortable in the water) but definitely not something that would venture on shore (like a crab) because I had undeniable problems entering and exiting the water from the shore. I'm not too smooth on land to begin with (as evidenced by my tripping as I walked away from the van towards my equipment), and even less so when I am stepping among tide pools and rocks with waves surging against my legs, an oxygen tank strapped to my back, and a mask on my face.
Despite the 10-15 minutes of concerted effort each entry and exit took, I decided to go swim at lunch today because as Wayne points out, SCUBA diving is a leisure activity, not a sport. Managed to do an easy 1km swim, with 5x100m on the 2:00. Not spectacular, but I wasn't pushing very hard and getting about 20 seconds rest.