Be careful not to let your dog spend too much time on hot sand or asphalt. Dogs can burn their feet just as easily as we can. Cool ocean water is very tempting to a dog. Don't allow your dog to drink too much sea water. Check with lifeguards for daily water conditions.
Dogs can be easy targets for jellyfish and sea lice.
Swimming is a great form of exercise for dogs, but don't let them overdo it. They will be using new muscles and may tire quickly.