I have been swimming for over 6 years in Cancun and my daughter is on a swim team so I am pretty familiar with all of the swim venues in pretty much the entire State. There are exactly 4,50 meter pools in Q,Roo 3 "Public" and one private (Albatros) of the public ones Playa, Cozumel and Cancun(actually Cozumels may be 25m) most of the year they are not even open or are man-made frog ponds. Anything that has to do with swimming depends on private citizens the Gov. is pathetic when it comes to any kind of sporting event. I am one of the "crazy people"that has a membership at Sport City and I love it, my daughter swims on the Squalos Team at St John's School. I spend about 1900.pesos a month on memberships and monthly dues for all 3 of us. I did swim in the ocean when I was training for OWS events and we generally swam at 7am from Punta Cancun to just past El Presidente and back it was around 3.5k. Another place that Squalos train at is from the first public beach (Las Perlas?) and there it is calmer with less current. You can swim laps at the Cruz Roja, St. Johns, Leonardo DaVinci, and Alexander school for a fee of around 650.00 pesos per month generally the hours are from 6 am to 9 am and from 7pm to 9pm.