What a coincidence. I have 3 golden retrievers. One is old, but the other two are 6 months (male) and 1 year (female). Both took to the pool immediately when we opened it this year. Especially the younger male. I discovered he was climbing the ladder and taking at least one swim in the morning and another dip in the afternoon. The female joined him sometimes.

http://www.jreece.com/Family/slides/Pool5.html

Our 27 ft round AG pool is butted against our deck so the step up is only about 2 feet to get in. So they could easily get in and out. I too was afraid they would tear the liner if we were not in with them, however in two weeks of morning and afternoon dips, they did not damage our liner. We may have just been lucky, but they seemed to know to go to the ladder to get out. However they left dirt and lots of hair in the pool.

I finally put a plastic fence around the part of the pool that butts up to the deck (approx 30%) and built a blockaid around the ladder using some thin plywood. This stopped them from getting in the pool unless we were there.

Jim