Lighthouse
In Calella I can strongly recomend to have tapas at Bar Calau (it can be busy but it is worth the wait) or lunch or dinner at Tragamar. Good food and wonderful sea view.
And if you like sushi you can have some at the Lighthouse (Far San Sebastien) in Llafranc at Farnomo.
The bay
In august it can be crowded during the day on the beach, even more so on the weekends because the people of Barcelona also like Tamariu!
Tamariu itself has a small but sheltered bay. The beach at LLafranc is even more beautiful and slightly wider. Especially suited for kids with nice sand and it slopes gently into the sea. But the one we like the most during peak season is found at La Castell. You should try it!
Hikes and culture
There is plenty to do and see in the area. There are several coastal walks.
If you go up the stairs next to the beach of Llafranc you can follow the path along the sea to Callela. It is a 10 to 15 minute walk (very easy) you will have a beautiful view and Callela is voted in the top ten best coastal towns of Spain.
There are plenty restaurants where you can have a drink before you go back.
Cap Roig, the botanical gardens in Callela are also worth a visit.
There is also a coastal path that starts at the Tamariu beach. This one is partly climbing over rocks so a little bit more difficult but also very much worth it. You can walk all the way to Llafranc (which will take several hours) or walk to Calla Pedrosa a tiny hidden bay with a small restaurant (only open in the high season).
If you go north you can visit Begur with it’s nice shops, restaurants and old castle on top of the hill. Or the beaches of Sa Riera and Sa Tuna.
Dali museum
And of course you can visit Barcelona, Girona (with the old Jewesh quarter) or Figueres with the Dali museum.
And there are two waterparks. One is only 15 minutes away in Platja D‘Aro and the other one a little bit further in Lloret de Mar. They both have a lot of slides but the one in Plata D’Aro is a little bit more family friendly. The other one can be crowded with youngster during summer.