On the west coast of Fuerteventura is a world famouse shipwreck of the SS American Star cruise liner. All local guide books have exact directions for finding this sight, but the journey is on unmade roads so a good quality rent-a-car will be needed.
Its a bit of a treck but well worth it.
Because of Corralejo's mostly unspoilt coastline and little seafaring traffic the are high levels of fish and similar in the waters, even in the harbour itself.
Fishing equipment can be hired from various places in old town, or bought relativley cheaply from one of its shops.
I regularly fish from the bottom of the harbour wall (beyond the ferry dock) and have caught a huge variety of tasty fish from sea bass to octopus. Usually between 12-2pm you will see dozens of local fisherman gutting and cleaning their days catch on several spots along the shoreline. Take a look at the tables next to the old pier on town beach.
These fish are often sold straight to local restaurants and if you time it right you can eat fresh fish that has never even seen a fridge.
If you have a go at catching one yourself, most harbour restaurants will cook it for you for a nominal fee.
Fuerteventura is a vulcanic Island so the landscape is pretty baron. But when you start to come into Corralejo you hit the Sand dunes, The sand blows across from Africa. This is an amazing sight. If you park your car on the side of the road BEWARE as the sand drifts and can cover your vehicle. We walked into the sand dunes and you feel like you are on another planet.
The sea cat trip was really good and is well worth the money. You have a BBQ on board and drinks are FREE. When you get to Lobos Island you can use the snorkeling gear or you can pay to go on the Jet Ski or the Banana Boat. Just to sit on the front of the catamaran with the wind in your face and the sun on your back is great.