1- Visit the Aquarium of Seville
In the Aquarium of Seville there are 400 different aquatic species and there are 5 different thematic zones: Guadalquivir, Atlantico, Pacific, and Indo-Pacific. The idea is to reproduce the travel made by Magellan in 1519 around the world. The best activity you can do there is to sleep with the sharks.
The aquarium is opened every day from 10AM. It is located in the Muelle de las Delicias (Port of Seville) and it is easy to reach with bicycle or with the bus. The price is 15€ but on Thursday you can visit it for only 10€ from 3PM.
2-Visit a Museum
Another activity you can do on a rainy day, is to visit a museum. Luckily for you, in Seville there are a lot of musea, and one for every taste. For contemporary art there is the Andalusian Contemporary Art Museum. It is located in Monasterio de la Cartuja de Santa María de Las Cuevas and it is opened from Tuesday to Sunday.
Another option is to go to Maria Luisa Park and see the Archaeological Museum and the Popular Arts Museum. There are many more to find in Seville, so just look for what interests you!
3-Visit the Cathedral
The Cathedral is for sure already on your list. As you spend your time here indoors, it is a perfect option to visit the Cathedral on a rainy day, so you won't miss a perfect sunny day because your indoors! It is the biggest Gothic cathedral and third largest church in the world. Moreover it contains the tomb of Christopher Columbus, lots of gold and a stuffed crocodile.
One of the best ways to spend a rainy day is surely by going shopping! In Nervion there is a big shoppng center, which is indoors! So, you can easily spend your day shopping for clothes, shoes, home decor, and more. You can also get some food and snacks, so your whole day can be fulfilled here!
5- Go to the cinema
A great way to spend your time on a grey, rainy day, is by going to the cinema to watch a movie. It may help improve your Spanish. But no worries, Seville has also two "original version" cinemas, in other words, the movies are here in English. The two cinemas are called: 'Avenida 5 Cines' and 'Cines Corona Center'.