Hi Isabel - I have an almost 5 month old and I use a ramp made of terry toweling in the baby bath. You can get them from Target for about $14 ish and they are great. The ramp is plastic and you can just slide the towel (which makes the ramp) off for washing. (Hope my description makes sense!) My DD loves lying on the ramp and splashes away and whilst I don't take my eyes away from her for a second she can lie there completely unaided. Only thing I'm not sure of is weight capacity as my DD is only just over 5kg - I'm sure it would be fine though!! Hope that hopes!