J.C.
My twins do this too. They are 2 and 1/2 but have been sleeping in the toddler beds/floor since about 20 months when the started climbing out of the crib and I was afraid they would get hurt.
I don't have any advice, I have tried several things none of which worked including letting them sleep on mattress on the floor and getting up several times to put them back in bed when I know they have gotten up.