Introduction: physical activity in infants through aquatic therapy is widely known for the later development of sensory ,cognitive and motor areas. In this way, babies will have a greater sense of freedom, pleasure and memory of the maternal uterus. In addition, the margin therapeutic safety in the water is very broad, which allows an optimal development of aquatic early stimulation programs.

Objective: To determine the relationship between aquatic physical activity in infants and the development of their psychomotor skills in their first year.

Methods: A prospective case-control study will take place for 12 months. Participating infants will be divided in two groups: an experimental group, which will be integrated by 74 babies who will participate with their parents in the aquatic physical activity programme in a heated pool (34-35ºC) and a control group with 71 babies who will not participate in the activities. The aquatic activity will consist on 20 minutes sessions twice a week.

Inclusion Criteria:

• Commitment to participate voluntarily.
• Signing informed consent to participate in the research, according to the Helsinki Declaration, updated at the 64th General Assembly, Fortaleza, Brazil, October 2013.

Exclusion Criteria:

• Babies who are born with a gestational age of less than 30 weeks.
• Baby changes that prevent physical activity.