One of the top things to do in Mallorca is a boat trip. Unfortunately, not all the boat trips are available in April. Most of the boat companies doesn’t start until May, especially the big catamarans. You can find some small catamaran options for maximum of 12 people available, but sometimes they require a minimum of people to run the trip.
Some great boat options in April are the boat trip to Formentor or the 1-hour boat trip in the bay of Palma. Another option available during Easter is the Sunrise and dolphin boat trip departing from Port de Alcudia. Sea temperature is maybe not perfect for humans, but for sure amazing for dolphins around the Balearic Islands.