I would like to ask you about small Muslim children who go to kindergarten or pre-school together with un-believers in non-Muslim countries. They adopt their habits and behaviour and way of speaking very quickly. Teacher doesn't respect their religion because especially our Czech society is mostly unbelieving. Is it better to prevent them from such schools and stay with them at home till they go to basic school? There are no Islamic schools, only one Arabic school which is expensive for many Muslim families in the Czech Republic but there is opportunity to educate children at home until ten years of age. What about ruling of children swimming? Can Muslim children go to swimming class with non-Muslim children and teacher if there are all children, women and men together and uncovering for us private parts of body because their swimming dress is not according Islamic rule?

Praise be to Allah, the Lord of the Worlds; and may His blessings and peace be upon our Prophet Muhammad and upon all his Family and Companions.

1) It is mandatory for anyone who is in charge of anything to fear Allah, by taking care of that matter and managing in the way that pleases Allah. No doubt that one of the most important priorities in this life is raising one's children. So, anyone who is responsible for children must take care of their physical and spiritual needs during childhood (and when older) as Allah Ordered that children be raised from their early age on good morals and right religion as part of their education even if they have not yet reached puberty. Parents are ordered to familiarize their children with the prayer, habituate them to it, and order them to perform it. They should also urge them to spread good morals. So, if the mentioned kindergarten will influence your children negatively by weakening their religious awareness, then it is unlawful for you to entangle your children in this infested swamp to avoid being the cause to their becoming ill-mannered and with a weak sense of religion. Throwing your children in such a bad environment makes them copy habits of disbelievers. On the other hand, teaching them at home might be sufficient and more appropriate and indeed Allah compensates whoever leaves something for His Sake with a better thing.
2) It is unlawful to let the children go to swimming pools where there are males and females exposing their Awrah. In fact, making the child familiar with such behaviour results in his accepting it and tolerating it. Allah Ordered the children not to enter their parents' bedroom at certain times when they might be uncovering their Awrah. Allah Says: {And when the children among you come to puberty, then let them (also) ask for permission, as those senior to them (in age). Thus Allâh makes clear His Ayât (Commandments and legal obligations) for you. And Allâh is All-Knowing, All-Wise.} [24: 59].
So, since Allah restrains entering one's parents bedroom for fear of seeing Awrah, then it is more prohibited to go to places where there is certainty to see Awrah uncovered.
We ask Allah to guide us and you to that which pleases Him
Allah knows best.