Well worth a look is The Ria Formosa lagoon, located in the Algarve, in southern Portugal, it is a system of barrier islands that communicates with the sea through six inlets. Five of these inlets are natural and have mobility characteristics. Wikipedia
More info:
http://www.formosamar.com/en/#.XKZpB_ZFyUk
https://www.algarvetouristguide.com/attractions/ria-formosa
There a quite a few different boat tour and dolphin watch operators located at Vilamoura Marina, in the Algarve region of Portugal. Each operator will have thier on unique offering, with some providing tours exclusively for adults and others that provide more suitable activities for families and younger explorers. The video on this page is from the www.watersportsvilamoura.com website.