Zakynthos
Zakynthos is a heaven for kids, with its many sandy beaches, its blue caves where you can snorkel, and its hiking on Skopos Hill. There are several water parks on the island, like Tsilivi Water Park and Zante Water Village. For more adventurous families, the kids will love exploring Navagio Beach, with its famous shipwreck. A recommended hotel for kids on Zakynthos is the Domes Aulus Zante, where kids can plant greens, herbs, and flowers with the KiEPOS program or hang out in their playrooms. On their website, Domes Aulus Zante features a “family” section with playtime activities for the kids, non-alcoholic drink menus, and activities for parents when their kids are with hotel staff.
Kos
Kos is an island in the Dodecanese chain and is an hour's flight from Athens. Kos has plenty of resorts to choose from for family, many of which are affordable and include beach clubs for the kids and kid-friendly pools. Kos is also known for its water parks, like the Lido Water Park, which has speed slides and a wave pool. Kids will love the many beaches on Kos Island, several of which have watersports and kid-friendly activities. Note that Kos is not as heavily touristed as the other islands on this list, so you will have more peace away from the crowds.