Spain has extended its covid restrictions on visitors from non-EU countries, including the UK. The restrictions have been extended until the 15th of July. They will then be reviewed again.
Currently, Non-EU counties require one of the following to enter Spain.
Double vaccination within 270 days from the second dose ( if you have had a booster shot, there is no time limit on this)
A negative PCR taken took no more than 72 hours before arrival.
A negative Antigen test taken no more than 24 hours prior to arrival.
A recovery cert between 11 days and 6 months after having had Covid.
The above applies to those age 12 and over.
Covid restrictions for EU counties were lifted last month.