Agree with Yasmin non slip bath mat on the bottom and a low amount of water xx
We just use a non slip bath mat since he could sit well unaided x
My boy turns 10 months tomorrow and we just use a non slip mat as he sits really well. We don't put much water in, the water barely reaches the top of his legs. He loves it! He plays with more toys in the bath this way too rather than the seat. We had the same seat and I was just sick of trying to get his legs in...
100% non slip bath mat. We got one from Amazon and he has so much fun in the bath now he can move about. He’s not slipped once
A non slip bath mat and then just hold baby/ have your hands ready to catch them. We’ve done it like this since 6 months when he grew out of the baby seat. I also find bath toys help keep him sat down/ distracted so he doesn’t try and crawl/ stand etc x