There are plenty of days that Punta Prima gets decent waves for surfing and especially paddleboarding. The beach can work and also out towards the point on the left. You'll usually have company but there is always a pleasant vibe in the water.
On flat days consider a paddle around the Island. It is a fair way out crossing the channel is quite exposed so pick your day carefully and be careful about any boats coming through. Fishing boats and pleasure craft head through at speed.
Officially the Illa Petita d'Addaia and the Illa Gran d'Addaia. It won't usually take that long to get round these islands. If it is nice and flat you could explore further along the coast westwards where there are a number of very pretty beaches with no public access over land. Usually a bit choppy outside the islands but calm inside. There is a beach to land on the side facing Addaia.
You also might want to head inland towards the saltings. Very peaceful up here and probably mirror calm. Excellent for bird life.
Isla d'es Bledes is quite a spectacular little island just under 3km paddle from Binimel·là - which is the nearest coastal access you can easily drive to. It is an along the coast paddle so not too intimidating although the island itself has high cliffs. The gap between the island and the north coast is a great place for snorkelling. I've always seen a great variety of fish here including large shoals of barracuda.
If you want to land on the island it is a bit of a scramble - be prepared to improvise. Views from the top are well worth it.
A very attractive and impressive circular paddle under the shadow of the imposing Cavalleria cliffs. Definitely one to do with a very still sea and minimal wind as there are no stopping points between start and finish, and it is a reasonably long distance.
You can either cut through the gap between the Isla Porros and the headland, or go round both.
A large bay with flat water, especially early morning and in the evenings, perfect for paddleboarding. There are numerous inlets and 3 islands to explore on the far side of the bay. The south of the bay is very shallow with lots of wildlife. Outside the bay there is plenty of cliff-lined coast to explore, and several caves, but the sea state is rarely truly flat, and passing boats create waves, so it is not such a relaxing experience.