The number of cot deaths in Wales have dropped by 64% over the past 11 years, according to the latest figures.
The Office for National Statistics (ONS) said there were 10 "sudden unexplained infant deaths" in 2015 with only north east England being lower.
It is the same figure as the previous year - down from the recorded 2004 high of 28 deaths.
Cot death charity The Lullaby Trust said promoting safer sleeping was one of the reasons behind the fall.
There were 191 unexplained infant deaths across England and Wales in 2015, accounting for 7.4% of all infant deaths that year.
Lowering the risk
- Always place your baby on their back to sleep
- Avoid smoking when pregnant or around the baby after it is born
- Place your baby in a separate cot or Moses basket in the same room as you for the first six months
- Use a good condition, firm, flat and waterproof mattress for your baby
- Never sleep on a sofa or in an armchair with your baby
- Do not sleep in the same bed as your baby if you smoke, drink or take drugs or are extremely tired
- Avoid letting your baby get too hot
- Do not cover your baby's face or head while they are sleeping or use loose bedding
Source: The Lullaby Trust
Francine Bates, chief executive of The Lullaby Trust said: "The number of sudden infant deaths has been steadily decreasing since the introduction of the back to sleep advice in 1991.
"If all health professionals and families follow the evidence-based safer sleep advice, we hope that the rate will halve by 2020."
The Lullaby Trust said the ONS could not say why deaths have dropped.
"However, it attributes it to a reduction in maternal smoking and an overall increased awareness of safer sleep advice," added Ms Bates.
Prof Jean White, chief nursing officer for Wales, welcomed the figures.
"Work is under way to reduce the incidence of low birth weight babies as this is a significant factor," she said
"The Safer Pregnancy campaign was launched in Wales in March 2017 that aims to inform women what they need to do to keep them and their baby safe in pregnancy.
"The campaign has three main principles - how women can help their baby, how professionals can help women and what women should ask their midwife about."