Because Benidorm itself is so well known I have chosen to concentrate on Benidorm Island. This small island also known as Peacock Island can be reached by ferry from Benidorm port for approx 10€ per person. This price includes a ticket for a trip on a semi-sub called an Aquascope. It only seats 24 so you may not get on the first one after your ferry lands but when you do you will be impressed by the views. The visibility can be excellent and the windows are kept clean as you can see from this photo.
You can spend as long as you want on the island just be careful not to miss the last ferry back. The island has been classified as a bird sanctuary and there is a path to the top with viewing points so you can get some unusual photographs of Benidorm.
While you are waiting for the ferry to take you back to the mainland there is a cafe serving drinks, snacks and meals.
Once you return to Benidorm itself from the port you can climb the steps up to the “mirador”. At the top you will see a small garden with a monument to the heroes of the sea by the side of a small church with blue domes. As you continue to the mirador itself you will pass a gazebo which is used for fiestas and weddings.