If you don't mind the somewhat tiring flight to the Seychelles, you can travel here with children without any worries. Direct flights from European cities take around 9 hours, while connecting flights take roughly twice as long. Regardless, Praslin and the other islands in the archipelago are suitable for family vacations.
The best beach for a family vacation with children on Praslin is Anse Volbert. It has calm waters with hardly any strong waves, and the sea is shallow. Even small children can safely play in the water. However, it may not be as interesting for adults who have to go quite far into deeper water. Nevertheless, children won't get too cold in the shallow and warm water. Plus, there are plenty of palm trees on the shore, providing excellent shade from the southern sun.
Praslin offers excellent infrastructure for family vacations with kids. There are numerous small hotels and guesthouses with a wide price range. Praslin is considered a somewhat expensive resort, with average hotel prices starting at around 250 EUR. However, there are seasonal discounts and budget options available for 100-150 EUR. Keep in mind that good hotels in Praslin have higher prices for family vacations, starting from 500 EUR per room.
Luxury hotels like Raffles Praslin and Iles des Palmes offer even higher prices, but they provide luxurious service. The island also has numerous stores and cafes. One minor drawback is that there can be occasional seaweed deposits at the water's edge on the sandy beach of Anse Volbert. However, hotel staff regularly clean them, so there's no garbage or odors, and the water remains quite clean, unlikely to spoil your vacation.