SpeedoEssential Endurance+ Medalist Swimsuit - Black, 28 (9-10 Years)

What is the sizing like for these swimsuits? looking for 8-9 or 9-10 years but not sure whether this would be s, m etc. can anyone advise please?

Hi,how do you find the size on the costume? Would like to buy the next size up for my daughter but cannot find the current size of her costume. Thanks

What size is a small in comparison to age 15-16 which is now too small for my small 12 year old! Looking for next size up.