For most children crying is developmentally appropriate and their only way of communicating. Typically once your child gains the confidence in their new skills the crying diminishes. Instructors are use to this behavior so don’t be concerned about tears interfering with lessons.
Learning new skills, with a new person, in a new environment; honestly who wouldn’t be upset at first? The cry we hear oftentimes in the water is the same cry you get when you take away a toy, don’t let them eat dirt, or even put them in their car seat. It’s a protest and their way of saying they aren’t happy to be here. Remember this is their way of communicating with us since most children are not yet verbal.
We like to tell parents/guardians that if you can make if through the first couple of weeks, it gets easier. Remember everyday at lessons is another day of building in-water confidence and another day closer to your child being fully skilled. You got this!