All Saints' Day is celebrated in Spain on the same day as in the rest of the world - on November 1.
How do the Spanish Celebrate All Saints' Day?
The most obvious sign that it is All Saints' Day is that you'll notice the graveyards to be unusually full of flowers. The Spanish remember their dearly departed on All Saints' Day and bring flowers to the graves of their loved ones on this day.
If you can get to see a performance of Don Juan Tenorio on All Saints' Day, seize the opportunity. The play is the most famous (and the most romantic) story about the mythical Don Juan and is performed each year on All Saints' Day.
There are a few traditional sweets that the Spanish eat on All Saints' Day. The most common is Huesos de Santo (literally 'saint's bones'), which is made of marzipan and 'dulce de yema'. Another is 'buñuelos de viento'.