Tested this summer for my son 7 months in pool and sea.
Only baby BĂ©mol sinks a little in and it therefore has some arms in the air but we deflated the cushion and went back the buoy and baby and therefore a little higher he can touch the water and swim. He feasted I highly recommend we could have a free hand and we have not been afraid it slides or drink the cup for his first time in the water!