We had a wonderful holiday with our 2 and 4 year olds. They absolutely loved the pool and we spent a lot of time at Ribeira d’Ilhas which is a lovely surf spot with a good restaurant.
If you can I would recommend getting a car. We went to the zoo in Lisbon and the Tapada in Mafra, but there are so many things to do. Claudia and Sonia were great hosts. The apartment is comfortable and they left toys for our children which made the holiday so much easier. You’ll have a great time here.