Individual Lesson, 30mins~45mins.
2 & 3 Students in a class, 45mins approx.
4 Students in a class, 45mins~60mins.
Note:
Individual Lesson
Children's attention span is generally shorter than adults. The duration of their 'learning curve' is about 30mins and it varies from child to child.
As the child is alone in the class, he/she gets all the attention they need from the instructor.
They will also have the luxury to continue swimming without having to wait for other children.
There is also a flipside, they may become very tired from the continuous swimming.
2 or more children in a class
Children develops faster and better when they interact with others.
Through interaction they will learn how to communicate, understand others and be able to understand the world better. From social interaction, they will learn about the social norm and rules that are not learnt from text books. Also through interaction the child will learn their 'position' in society and other values like respect for others and such.
General
We adults have our so called 'off-days', when things do not go on as smoothly as we wanted/planned. Children too have these kind of days. We have to be careful not to force them to continue swimming as they may develop negative feeling towards swimming.
Rest assured that when there are days that lessons are short, there will be days that lessons are longer.