The Zoomarine close to Club Albufeira in the central Algarve region is open all year round and makes a wonderful day out for families.
A quote from the site
"Zoomarine Portugal has been running for more than ten years and every
year attracts thousands of visitors from all over the world.
Enter into Zoomarine and dive into a fantastic reality made up of
unique shows and emotions, observe the special relationship between
animals and humans. Amazing shows and experiences and the pleasure to
find yourself in a stimulating reality are guaranteed. "
It provides a programme for swimming with the Dolphins with photos and a video of the event for your memories.